<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with Wdesk from Workiva-->
<!--Copyright 2021 Workiva-->
<!--r:8df4df75-4371-4fb9-a8c6-72361a0feb44,g:edeeaad3-50e1-44dc-8677-865e7c4937a5-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.commvault.com/role/ConsolidatedStatementsofOperations" xlink:type="simple" xlink:href="cvlt-20210930.xsd#ConsolidatedStatementsofOperations"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/ConsolidatedStatementsofOperations" xlink:type="extended" id="i816675a48a7a403f99fd5619c899fa47_ConsolidatedStatementsofOperations">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerAbstract_400235a0-6179-4119-9537-94ff475d967a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerAbstract_400235a0-6179-4119-9537-94ff475d967a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_de7b3559-badd-4f3a-9fae-de585f5db623" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueFromContractWithCustomerAbstract_400235a0-6179-4119-9537-94ff475d967a" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_de7b3559-badd-4f3a-9fae-de585f5db623" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_a79ca295-7898-4d55-84db-9b571f7a43f9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServicesSoldAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_a79ca295-7898-4d55-84db-9b571f7a43f9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsAndServicesSold_2b10b29d-fa87-4328-9cde-dcd8b8582ccf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CostOfGoodsAndServicesSold"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CostOfGoodsAndServicesSoldAbstract_a79ca295-7898-4d55-84db-9b571f7a43f9" xlink:to="loc_us-gaap_CostOfGoodsAndServicesSold_2b10b29d-fa87-4328-9cde-dcd8b8582ccf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GrossProfit_94cbbc0d-d2b8-4d98-9f2e-88610d783d08" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GrossProfit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_GrossProfit_94cbbc0d-d2b8-4d98-9f2e-88610d783d08" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpensesAbstract_67d90c75-5702-4ee6-ae36-f433e2e7b8be" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingExpensesAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_OperatingExpensesAbstract_67d90c75-5702-4ee6-ae36-f433e2e7b8be" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpense_0fd10fb3-4abd-40ca-87ca-90891a4b8d75" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingAndMarketingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_67d90c75-5702-4ee6-ae36-f433e2e7b8be" xlink:to="loc_us-gaap_SellingAndMarketingExpense_0fd10fb3-4abd-40ca-87ca-90891a4b8d75" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpense_13ce7d29-e380-433e-a172-08e814dcbd23" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResearchAndDevelopmentExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_67d90c75-5702-4ee6-ae36-f433e2e7b8be" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpense_13ce7d29-e380-433e-a172-08e814dcbd23" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpense_6b5187f0-2a93-48b5-a8ba-69c34df59ca9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralAndAdministrativeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_67d90c75-5702-4ee6-ae36-f433e2e7b8be" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpense_6b5187f0-2a93-48b5-a8ba-69c34df59ca9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_d33a5ef5-bce0-41ec-b4d2-826e28be90a9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_67d90c75-5702-4ee6-ae36-f433e2e7b8be" xlink:to="loc_us-gaap_RestructuringCharges_d33a5ef5-bce0-41ec-b4d2-826e28be90a9" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_7aece4cc-c6d3-4d9a-9f83-c7ebb46ac8e6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ImpairmentOfIntangibleAssetsFinitelived"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_67d90c75-5702-4ee6-ae36-f433e2e7b8be" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsFinitelived_7aece4cc-c6d3-4d9a-9f83-c7ebb46ac8e6" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationAndAmortization_20972115-f515-49b5-9a90-59cdf6f81361" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DepreciationAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_67d90c75-5702-4ee6-ae36-f433e2e7b8be" xlink:to="loc_us-gaap_DepreciationAndAmortization_20972115-f515-49b5-9a90-59cdf6f81361" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingExpenses_afa7060b-b1e7-4af6-a6ce-3130ec14ee6c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingExpenses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingExpensesAbstract_67d90c75-5702-4ee6-ae36-f433e2e7b8be" xlink:to="loc_us-gaap_OperatingExpenses_afa7060b-b1e7-4af6-a6ce-3130ec14ee6c" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_318ead72-34a9-4680-af09-b44249bfd153" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_OperatingIncomeLoss_318ead72-34a9-4680-af09-b44249bfd153" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentIncomeInterest_72eed8fd-6228-4847-986b-576cd8efa21b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentIncomeInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_InvestmentIncomeInterest_72eed8fd-6228-4847-986b-576cd8efa21b" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_83df0030-4b27-4e9a-b53e-e729c8a9c48d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_83df0030-4b27-4e9a-b53e-e729c8a9c48d" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_beaa1c3a-2b51-4e48-9594-1d2ba4784b08" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_beaa1c3a-2b51-4e48-9594-1d2ba4784b08" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_d693d242-460a-4d88-b937-1a0269db46bb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_NetIncomeLoss_d693d242-460a-4d88-b937-1a0269db46bb" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareAbstract_3f671e52-07d7-4bc2-b3f1-be9a9d62ba4a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_EarningsPerShareAbstract_3f671e52-07d7-4bc2-b3f1-be9a9d62ba4a" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareBasic_2514a592-686a-4a04-afe8-66992126a599" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_3f671e52-07d7-4bc2-b3f1-be9a9d62ba4a" xlink:to="loc_us-gaap_EarningsPerShareBasic_2514a592-686a-4a04-afe8-66992126a599" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDiluted_6d85e328-d135-4a3f-b8e7-355960744fc7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareDiluted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EarningsPerShareAbstract_3f671e52-07d7-4bc2-b3f1-be9a9d62ba4a" xlink:to="loc_us-gaap_EarningsPerShareDiluted_6d85e328-d135-4a3f-b8e7-355960744fc7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c57a69ce-c023-4511-b16b-d71543c90f7b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c57a69ce-c023-4511-b16b-d71543c90f7b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_358981fd-673f-4cf5-9aa8-42d03b50a895" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c57a69ce-c023-4511-b16b-d71543c90f7b" xlink:to="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_358981fd-673f-4cf5-9aa8-42d03b50a895" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_aec89511-bb9d-4687-85a4-3092e919a1da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_c57a69ce-c023-4511-b16b-d71543c90f7b" xlink:to="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_aec89511-bb9d-4687-85a4-3092e919a1da" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_c277ec7b-7991-4c7c-baf8-16e2cae68490" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_ede8fd3a-4927-410f-8fa2-0030aa074e23" xlink:to="loc_us-gaap_StatementTable_c277ec7b-7991-4c7c-baf8-16e2cae68490" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_8feb4b33-e095-43ef-99d1-664588634b37" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_c277ec7b-7991-4c7c-baf8-16e2cae68490" xlink:to="loc_srt_ProductOrServiceAxis_8feb4b33-e095-43ef-99d1-664588634b37" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8feb4b33-e095-43ef-99d1-664588634b37_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_8feb4b33-e095-43ef-99d1-664588634b37" xlink:to="loc_srt_ProductsAndServicesDomain_8feb4b33-e095-43ef-99d1-664588634b37_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_d991baff-e99e-491d-bf3d-c0f0dbd6df47" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_8feb4b33-e095-43ef-99d1-664588634b37" xlink:to="loc_srt_ProductsAndServicesDomain_d991baff-e99e-491d-bf3d-c0f0dbd6df47" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_b27d9b60-cc98-48d0-82b6-3aa94e0dc06b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d991baff-e99e-491d-bf3d-c0f0dbd6df47" xlink:to="loc_us-gaap_ProductMember_b27d9b60-cc98-48d0-82b6-3aa94e0dc06b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceMember_37a2b52b-4bf9-4e55-8057-5a1e6c8b037f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_d991baff-e99e-491d-bf3d-c0f0dbd6df47" xlink:to="loc_us-gaap_ServiceMember_37a2b52b-4bf9-4e55-8057-5a1e6c8b037f" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="simple" xlink:href="cvlt-20210930.xsd#ConsolidatedStatementsofStockholdersEquity"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="extended" id="i80b27643d28e431886527e73c91f2e83_ConsolidatedStatementsofStockholdersEquity">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_dd2a06f1-67a9-4316-9bfe-1621ce2a4ed9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_dd2a06f1-67a9-4316-9bfe-1621ce2a4ed9" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_5253f0a4-b4ba-4c0f-8f95-20b6360d25a4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:to="loc_us-gaap_SharesOutstanding_5253f0a4-b4ba-4c0f-8f95-20b6360d25a4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_1917a0a8-30db-4d9c-b458-20d6affd6d90" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:to="loc_us-gaap_StockholdersEquity_1917a0a8-30db-4d9c-b458-20d6affd6d90" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_3f3e62de-ec58-4253-978b-77cccdac60c0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_3f3e62de-ec58-4253-978b-77cccdac60c0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_a2984fc6-5d3a-408e-8645-d7ae4b544561" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_a2984fc6-5d3a-408e-8645-d7ae4b544561" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_e73560da-1731-4ce1-96a0-cb9b69eaa6c2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_e73560da-1731-4ce1-96a0-cb9b69eaa6c2" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_27133912-f38e-43f9-9adf-f05a415bc638" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_27133912-f38e-43f9-9adf-f05a415bc638" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_f84864f4-d6d0-4460-bfb2-23686c89c6e0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_f84864f4-d6d0-4460-bfb2-23686c89c6e0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingStandardsUpdateExtensibleList_43edb7fb-92f5-455d-94b3-a60d14fd9c5b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountingStandardsUpdateExtensibleList"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:to="loc_us-gaap_AccountingStandardsUpdateExtensibleList_43edb7fb-92f5-455d-94b3-a60d14fd9c5b" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_aec27d14-fdcf-4de7-8907-97d95f81b3c5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:to="loc_us-gaap_NetIncomeLoss_aec27d14-fdcf-4de7-8907-97d95f81b3c5" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_50720a6c-c7c5-46ff-9a03-65fd3a4b2476" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_0943de62-3cad-4056-9803-fac86dc5f02b" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_50720a6c-c7c5-46ff-9a03-65fd3a4b2476" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesOutstanding_b238cbc6-ac23-4304-b27e-bbacade4ca93" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharesOutstanding"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_4e9f4fe9-d065-426e-91de-4027374cbdf2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_03b8f995-0875-43e3-b297-0d6cc0c54a7a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_dd2a06f1-67a9-4316-9bfe-1621ce2a4ed9" xlink:to="loc_us-gaap_StatementTable_03b8f995-0875-43e3-b297-0d6cc0c54a7a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_76eefd20-8292-4c0b-84a8-63ae2a8d536e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_03b8f995-0875-43e3-b297-0d6cc0c54a7a" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_76eefd20-8292-4c0b-84a8-63ae2a8d536e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_76eefd20-8292-4c0b-84a8-63ae2a8d536e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_76eefd20-8292-4c0b-84a8-63ae2a8d536e" xlink:to="loc_us-gaap_EquityComponentDomain_76eefd20-8292-4c0b-84a8-63ae2a8d536e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_131eb52c-30d7-4ec6-a8c1-7173c775ab4c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_76eefd20-8292-4c0b-84a8-63ae2a8d536e" xlink:to="loc_us-gaap_EquityComponentDomain_131eb52c-30d7-4ec6-a8c1-7173c775ab4c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_ed372d75-bca3-4c15-bfeb-3a7c207506b2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_131eb52c-30d7-4ec6-a8c1-7173c775ab4c" xlink:to="loc_us-gaap_CommonStockMember_ed372d75-bca3-4c15-bfeb-3a7c207506b2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_4f5fd91d-a329-499d-bbce-42bc23eda598" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_131eb52c-30d7-4ec6-a8c1-7173c775ab4c" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_4f5fd91d-a329-499d-bbce-42bc23eda598" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_6177f745-c94e-4334-a929-41a88e03b4b9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_131eb52c-30d7-4ec6-a8c1-7173c775ab4c" xlink:to="loc_us-gaap_RetainedEarningsMember_6177f745-c94e-4334-a929-41a88e03b4b9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f9b03149-b38a-41e9-8d42-d3d062b155ae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_131eb52c-30d7-4ec6-a8c1-7173c775ab4c" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_f9b03149-b38a-41e9-8d42-d3d062b155ae" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_01fa621f-0edf-4a01-8c9c-ffe4cb263073" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_03b8f995-0875-43e3-b297-0d6cc0c54a7a" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_01fa621f-0edf-4a01-8c9c-ffe4cb263073" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_01fa621f-0edf-4a01-8c9c-ffe4cb263073_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_01fa621f-0edf-4a01-8c9c-ffe4cb263073" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_01fa621f-0edf-4a01-8c9c-ffe4cb263073_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_27dc0b80-58e3-4ffa-9e0a-31701dc47cb3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionAxis_01fa621f-0edf-4a01-8c9c-ffe4cb263073" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_27dc0b80-58e3-4ffa-9e0a-31701dc47cb3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_cc6174fc-e20c-40ea-adc0-40c83a1831ea" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_CumulativeEffectPeriodOfAdoptionDomain_27dc0b80-58e3-4ffa-9e0a-31701dc47cb3" xlink:to="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_cc6174fc-e20c-40ea-adc0-40c83a1831ea" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/SummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#SummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/SummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails" xlink:type="extended" id="i166bef7c68f74e6391fa08f70123876c_SummaryofSignificantAccountingPoliciesConcentrationofCreditRiskDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_43966c59-09f7-4f2a-b9a0-8c3fb6fb26df" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_04193038-f83f-4fe7-ae93-457a0ac12e0c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_43966c59-09f7-4f2a-b9a0-8c3fb6fb26df" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_04193038-f83f-4fe7-ae93-457a0ac12e0c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_6a75df84-63de-49e3-abb0-b38c912e1a99" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_43966c59-09f7-4f2a-b9a0-8c3fb6fb26df" xlink:to="loc_us-gaap_ConcentrationRiskTable_6a75df84-63de-49e3-abb0-b38c912e1a99" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_58c4e451-ed12-432b-9001-ebae01d085da" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_6a75df84-63de-49e3-abb0-b38c912e1a99" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_58c4e451-ed12-432b-9001-ebae01d085da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_58c4e451-ed12-432b-9001-ebae01d085da_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_58c4e451-ed12-432b-9001-ebae01d085da" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_58c4e451-ed12-432b-9001-ebae01d085da_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_a1b954d9-38f2-460d-b6af-55f89ffaa848" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_58c4e451-ed12-432b-9001-ebae01d085da" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_a1b954d9-38f2-460d-b6af-55f89ffaa848" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_bc8e1ac6-4218-4ea9-aba5-ccffd98942d5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_a1b954d9-38f2-460d-b6af-55f89ffaa848" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_bc8e1ac6-4218-4ea9-aba5-ccffd98942d5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_cf917c69-65bc-477f-9639-76e07c7a9764" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_6a75df84-63de-49e3-abb0-b38c912e1a99" xlink:to="loc_srt_MajorCustomersAxis_cf917c69-65bc-477f-9639-76e07c7a9764" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_cf917c69-65bc-477f-9639-76e07c7a9764_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_cf917c69-65bc-477f-9639-76e07c7a9764" xlink:to="loc_srt_NameOfMajorCustomerDomain_cf917c69-65bc-477f-9639-76e07c7a9764_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_4422c1d1-b04c-46ae-851e-b8dcbb6be1c3" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_cf917c69-65bc-477f-9639-76e07c7a9764" xlink:to="loc_srt_NameOfMajorCustomerDomain_4422c1d1-b04c-46ae-851e-b8dcbb6be1c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ArrowMember_4d4ded81-2c7e-4519-8363-2763c631d8f9" xlink:href="cvlt-20210930.xsd#cvlt_ArrowMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_4422c1d1-b04c-46ae-851e-b8dcbb6be1c3" xlink:to="loc_cvlt_ArrowMember_4d4ded81-2c7e-4519-8363-2763c631d8f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_TechDataMember_8ecdc604-fd36-480e-9c50-3354a1d8e576" xlink:href="cvlt-20210930.xsd#cvlt_TechDataMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_4422c1d1-b04c-46ae-851e-b8dcbb6be1c3" xlink:to="loc_cvlt_TechDataMember_8ecdc604-fd36-480e-9c50-3354a1d8e576" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_d2da7ab6-b770-45cd-a3d0-742b59a69dd9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_6a75df84-63de-49e3-abb0-b38c912e1a99" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_d2da7ab6-b770-45cd-a3d0-742b59a69dd9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_d2da7ab6-b770-45cd-a3d0-742b59a69dd9_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_d2da7ab6-b770-45cd-a3d0-742b59a69dd9" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_d2da7ab6-b770-45cd-a3d0-742b59a69dd9_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_c97274db-ade9-4df7-a315-8a15f6dc745d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_d2da7ab6-b770-45cd-a3d0-742b59a69dd9" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_c97274db-ade9-4df7-a315-8a15f6dc745d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_90076b3f-12bb-4952-93f5-61335eef531a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_c97274db-ade9-4df7-a315-8a15f6dc745d" xlink:to="loc_us-gaap_SalesRevenueNetMember_90076b3f-12bb-4952-93f5-61335eef531a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_23726726-ed0d-408f-9107-56cd05e7ddae" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_c97274db-ade9-4df7-a315-8a15f6dc745d" xlink:to="loc_us-gaap_AccountsReceivableMember_23726726-ed0d-408f-9107-56cd05e7ddae" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/SummaryofSignificantAccountingPoliciesEquitySecuritiesAccountedforatNetAssetValueDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#SummaryofSignificantAccountingPoliciesEquitySecuritiesAccountedforatNetAssetValueDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/SummaryofSignificantAccountingPoliciesEquitySecuritiesAccountedforatNetAssetValueDetails" xlink:type="extended" id="i872f3c77bc01404c8f8a6399e67056ea_SummaryofSignificantAccountingPoliciesEquitySecuritiesAccountedforatNetAssetValueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_abdaa56c-b94d-4f77-bf30-8defc406b417" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent_c48bd81d-8dfd-472b-b618-a2dde7469497" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_abdaa56c-b94d-4f77-bf30-8defc406b417" xlink:to="loc_us-gaap_EquitySecuritiesFvNiCurrentAndNoncurrent_c48bd81d-8dfd-472b-b618-a2dde7469497" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments_3b6f4d4b-6b3d-4811-9500-a7d184469cba" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_abdaa56c-b94d-4f77-bf30-8defc406b417" xlink:to="loc_us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments_3b6f4d4b-6b3d-4811-9500-a7d184469cba" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_cf0a2ff6-4030-4800-90a6-76582213dde3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEquityMethodInvestmentsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_abdaa56c-b94d-4f77-bf30-8defc406b417" xlink:to="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_cf0a2ff6-4030-4800-90a6-76582213dde3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeAxis_4fc3cc87-78a3-42bc-be1a-01803d4e972f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEquityMethodInvestmentsTable_cf0a2ff6-4030-4800-90a6-76582213dde3" xlink:to="loc_us-gaap_InvestmentTypeAxis_4fc3cc87-78a3-42bc-be1a-01803d4e972f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_4fc3cc87-78a3-42bc-be1a-01803d4e972f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_4fc3cc87-78a3-42bc-be1a-01803d4e972f" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_4fc3cc87-78a3-42bc-be1a-01803d4e972f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_796edc5d-0255-4701-b805-961345df9d52" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_4fc3cc87-78a3-42bc-be1a-01803d4e972f" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_796edc5d-0255-4701-b805-961345df9d52" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrivateEquityFundsMember_72d2e990-991e-4ea4-9f51-a3f8a17d0645" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PrivateEquityFundsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_796edc5d-0255-4701-b805-961345df9d52" xlink:to="loc_us-gaap_PrivateEquityFundsMember_72d2e990-991e-4ea4-9f51-a3f8a17d0645" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/SummaryofSignificantAccountingPoliciesDeferredCommissionsCostDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#SummaryofSignificantAccountingPoliciesDeferredCommissionsCostDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/SummaryofSignificantAccountingPoliciesDeferredCommissionsCostDetails" xlink:type="extended" id="ib6524b4a885546a9af4825647e2064eb_SummaryofSignificantAccountingPoliciesDeferredCommissionsCostDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems_f8764cf0-3195-4be6-be5e-96b9f225ca4c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpense_72ca7cb6-ff54-46bd-affb-eff0e685e0db" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingAndMarketingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems_f8764cf0-3195-4be6-be5e-96b9f225ca4c" xlink:to="loc_us-gaap_SellingAndMarketingExpense_72ca7cb6-ff54-46bd-affb-eff0e685e0db" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable_cea3e243-f8e9-45dc-ae19-a9f031360c9d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ErrorCorrectionsAndPriorPeriodAdjustmentsRestatementLineItems_f8764cf0-3195-4be6-be5e-96b9f225ca4c" xlink:to="loc_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable_cea3e243-f8e9-45dc-ae19-a9f031360c9d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis_0448e9c0-8bf0-4a75-9774-d6cfd6ea549d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfErrorCorrectionsAndPriorPeriodAdjustmentRestatementTable_cea3e243-f8e9-45dc-ae19-a9f031360c9d" xlink:to="loc_us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis_0448e9c0-8bf0-4a75-9774-d6cfd6ea549d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingPrincipleMember_0448e9c0-8bf0-4a75-9774-d6cfd6ea549d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ChangeInAccountingPrincipleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis_0448e9c0-8bf0-4a75-9774-d6cfd6ea549d" xlink:to="loc_us-gaap_ChangeInAccountingPrincipleMember_0448e9c0-8bf0-4a75-9774-d6cfd6ea549d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ChangeInAccountingPrincipleMember_51d052b8-e991-4ca3-ba86-0cecfae75126" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ChangeInAccountingPrincipleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AdjustmentsForChangeInAccountingPrincipleAxis_0448e9c0-8bf0-4a75-9774-d6cfd6ea549d" xlink:to="loc_us-gaap_ChangeInAccountingPrincipleMember_51d052b8-e991-4ca3-ba86-0cecfae75126" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_CommissionPlansModificationMember_ba0d1bc6-477f-48ef-81bc-ccc338221ce1" xlink:href="cvlt-20210930.xsd#cvlt_CommissionPlansModificationMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ChangeInAccountingPrincipleMember_51d052b8-e991-4ca3-ba86-0cecfae75126" xlink:to="loc_cvlt_CommissionPlansModificationMember_ba0d1bc6-477f-48ef-81bc-ccc338221ce1" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/RevenueAdditionalInformationDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#RevenueAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/RevenueAdditionalInformationDetails" xlink:type="extended" id="ibf3314a3931f4f27be3e50a74ff9d2d8_RevenueAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_3e6d7047-841e-43e8-970d-ab0e62998f3d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_3e7a4292-6a20-4c7d-829e-6922deeaf897" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_3e6d7047-841e-43e8-970d-ab0e62998f3d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_3e7a4292-6a20-4c7d-829e-6922deeaf897" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_96632eaa-a5e8-4a78-aa0d-5ff7f51991b3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_3e6d7047-841e-43e8-970d-ab0e62998f3d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_96632eaa-a5e8-4a78-aa0d-5ff7f51991b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_e25ec45d-8737-4bf0-9831-d0af27a0ca3c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_3e6d7047-841e-43e8-970d-ab0e62998f3d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_e25ec45d-8737-4bf0-9831-d0af27a0ca3c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_7205e58c-ef07-470d-aec2-51f3f7686681" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_e25ec45d-8737-4bf0-9831-d0af27a0ca3c" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionStartDateAxis_7205e58c-ef07-470d-aec2-51f3f7686681" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_8e0c7bea-4a98-47e7-b274-4ebbd408186d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_e25ec45d-8737-4bf0-9831-d0af27a0ca3c" xlink:to="loc_srt_ProductOrServiceAxis_8e0c7bea-4a98-47e7-b274-4ebbd408186d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8e0c7bea-4a98-47e7-b274-4ebbd408186d_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_8e0c7bea-4a98-47e7-b274-4ebbd408186d" xlink:to="loc_srt_ProductsAndServicesDomain_8e0c7bea-4a98-47e7-b274-4ebbd408186d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8011b8cf-0ef1-4616-85f7-6d4815bfebdd" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_8e0c7bea-4a98-47e7-b274-4ebbd408186d" xlink:to="loc_srt_ProductsAndServicesDomain_8011b8cf-0ef1-4616-85f7-6d4815bfebdd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_bfe7b080-8262-474c-a22d-dd18e6f24491" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8011b8cf-0ef1-4616-85f7-6d4815bfebdd" xlink:to="loc_us-gaap_ProductMember_bfe7b080-8262-474c-a22d-dd18e6f24491" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ProfessionalServicesOtherMember_6691d3d2-b270-4d4e-8ffd-7d4e422f26d0" xlink:href="cvlt-20210930.xsd#cvlt_ProfessionalServicesOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8011b8cf-0ef1-4616-85f7-6d4815bfebdd" xlink:to="loc_cvlt_ProfessionalServicesOtherMember_6691d3d2-b270-4d4e-8ffd-7d4e422f26d0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/RevenueAdditionalInformationDetails_1" xlink:type="simple" xlink:href="cvlt-20210930.xsd#RevenueAdditionalInformationDetails_1"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/RevenueAdditionalInformationDetails_1" xlink:type="extended" id="i19a6951d8db84d29bdfe7cc685fb4692_RevenueAdditionalInformationDetails_1">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_3e6d7047-841e-43e8-970d-ab0e62998f3d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligation_3e7a4292-6a20-4c7d-829e-6922deeaf897" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_3e6d7047-841e-43e8-970d-ab0e62998f3d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligation_3e7a4292-6a20-4c7d-829e-6922deeaf897" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_96632eaa-a5e8-4a78-aa0d-5ff7f51991b3" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_3e6d7047-841e-43e8-970d-ab0e62998f3d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_96632eaa-a5e8-4a78-aa0d-5ff7f51991b3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_e25ec45d-8737-4bf0-9831-d0af27a0ca3c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_3e6d7047-841e-43e8-970d-ab0e62998f3d" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_e25ec45d-8737-4bf0-9831-d0af27a0ca3c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_8e0c7bea-4a98-47e7-b274-4ebbd408186d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_e25ec45d-8737-4bf0-9831-d0af27a0ca3c" xlink:to="loc_srt_ProductOrServiceAxis_8e0c7bea-4a98-47e7-b274-4ebbd408186d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8e0c7bea-4a98-47e7-b274-4ebbd408186d_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_8e0c7bea-4a98-47e7-b274-4ebbd408186d" xlink:to="loc_srt_ProductsAndServicesDomain_8e0c7bea-4a98-47e7-b274-4ebbd408186d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_8011b8cf-0ef1-4616-85f7-6d4815bfebdd" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_8e0c7bea-4a98-47e7-b274-4ebbd408186d" xlink:to="loc_srt_ProductsAndServicesDomain_8011b8cf-0ef1-4616-85f7-6d4815bfebdd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_bfe7b080-8262-474c-a22d-dd18e6f24491" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8011b8cf-0ef1-4616-85f7-6d4815bfebdd" xlink:to="loc_us-gaap_ProductMember_bfe7b080-8262-474c-a22d-dd18e6f24491" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ProfessionalServicesOtherMember_6691d3d2-b270-4d4e-8ffd-7d4e422f26d0" xlink:href="cvlt-20210930.xsd#cvlt_ProfessionalServicesOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_8011b8cf-0ef1-4616-85f7-6d4815bfebdd" xlink:to="loc_cvlt_ProfessionalServicesOtherMember_6691d3d2-b270-4d4e-8ffd-7d4e422f26d0" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/RevenuePerformanceObligationsDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#RevenuePerformanceObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/RevenuePerformanceObligationsDetails" xlink:type="extended" id="i1b36ef1324034278bbcb584d441acee7_RevenuePerformanceObligationsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_56d9ea6e-e79a-4e51-9a94-58c74648a561" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_RevenuePerformanceObligationDescriptionOfPaymentTermsPeriod_beb14ebd-c0ad-4ba0-a553-633a7b509394" xlink:href="cvlt-20210930.xsd#cvlt_RevenuePerformanceObligationDescriptionOfPaymentTermsPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_56d9ea6e-e79a-4e51-9a94-58c74648a561" xlink:to="loc_cvlt_RevenuePerformanceObligationDescriptionOfPaymentTermsPeriod_beb14ebd-c0ad-4ba0-a553-633a7b509394" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_03ada38e-c3be-49ae-aacd-e6c515e6cf62" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionLineItems_56d9ea6e-e79a-4e51-9a94-58c74648a561" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_03ada38e-c3be-49ae-aacd-e6c515e6cf62" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_3594ef37-9aa7-4698-b87f-5c6c83cdd2b8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionTable_03ada38e-c3be-49ae-aacd-e6c515e6cf62" xlink:to="loc_srt_ProductOrServiceAxis_3594ef37-9aa7-4698-b87f-5c6c83cdd2b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_3594ef37-9aa7-4698-b87f-5c6c83cdd2b8_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_3594ef37-9aa7-4698-b87f-5c6c83cdd2b8" xlink:to="loc_srt_ProductsAndServicesDomain_3594ef37-9aa7-4698-b87f-5c6c83cdd2b8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_c1db98e0-92d3-4b84-a4af-534f65bf6d86" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_3594ef37-9aa7-4698-b87f-5c6c83cdd2b8" xlink:to="loc_srt_ProductsAndServicesDomain_c1db98e0-92d3-4b84-a4af-534f65bf6d86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_SoftwareLicensesMember_e902cc05-498f-4ca9-8d08-7d1cc7a099cf" xlink:href="cvlt-20210930.xsd#cvlt_SoftwareLicensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_c1db98e0-92d3-4b84-a4af-534f65bf6d86" xlink:to="loc_cvlt_SoftwareLicensesMember_e902cc05-498f-4ca9-8d08-7d1cc7a099cf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ProfessionalServicesOtherMember_4f9f6685-4cd2-4150-b60a-3b42d5b2cc70" xlink:href="cvlt-20210930.xsd#cvlt_ProfessionalServicesOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_c1db98e0-92d3-4b84-a4af-534f65bf6d86" xlink:to="loc_cvlt_ProfessionalServicesOtherMember_4f9f6685-4cd2-4150-b60a-3b42d5b2cc70" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ProfessionalServicesEducationServicesMember_8574986e-1285-414c-9f71-1f5c62f4b56c" xlink:href="cvlt-20210930.xsd#cvlt_ProfessionalServicesEducationServicesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_c1db98e0-92d3-4b84-a4af-534f65bf6d86" xlink:to="loc_cvlt_ProfessionalServicesEducationServicesMember_8574986e-1285-414c-9f71-1f5c62f4b56c" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/RevenueDisaggregationofRevenueDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#RevenueDisaggregationofRevenueDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/RevenueDisaggregationofRevenueDetails" xlink:type="extended" id="ie088a0907bc14af3a14f35c5c13d60fc_RevenueDisaggregationofRevenueDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_e501f8d8-78e9-4fd9-9b2c-df9e01338d2d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_6bc6bc5e-3365-44a6-961d-6f7b010ecce0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_e501f8d8-78e9-4fd9-9b2c-df9e01338d2d" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_6bc6bc5e-3365-44a6-961d-6f7b010ecce0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_469dc908-38e0-4122-8a5e-295a138ce9a6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_e501f8d8-78e9-4fd9-9b2c-df9e01338d2d" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_469dc908-38e0-4122-8a5e-295a138ce9a6" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_12cbcc5d-b18e-4cb9-ae14-6e85427ec527" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_469dc908-38e0-4122-8a5e-295a138ce9a6" xlink:to="loc_srt_ProductOrServiceAxis_12cbcc5d-b18e-4cb9-ae14-6e85427ec527" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_12cbcc5d-b18e-4cb9-ae14-6e85427ec527_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_12cbcc5d-b18e-4cb9-ae14-6e85427ec527" xlink:to="loc_srt_ProductsAndServicesDomain_12cbcc5d-b18e-4cb9-ae14-6e85427ec527_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_b42bcb29-9f9a-44b4-913d-85b2b0aeeaca" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_12cbcc5d-b18e-4cb9-ae14-6e85427ec527" xlink:to="loc_srt_ProductsAndServicesDomain_b42bcb29-9f9a-44b4-913d-85b2b0aeeaca" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProductMember_d2c02be6-5618-4e4b-a995-bf3b718d6913" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProductMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_b42bcb29-9f9a-44b4-913d-85b2b0aeeaca" xlink:to="loc_us-gaap_ProductMember_d2c02be6-5618-4e4b-a995-bf3b718d6913" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_CustomerSupportServiceMember_dc8d6020-c487-421b-bffa-f2c9ad25da45" xlink:href="cvlt-20210930.xsd#cvlt_CustomerSupportServiceMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_b42bcb29-9f9a-44b4-913d-85b2b0aeeaca" xlink:to="loc_cvlt_CustomerSupportServiceMember_dc8d6020-c487-421b-bffa-f2c9ad25da45" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ServiceOtherMember_91b5e31a-4cf3-43d0-ad3d-485743b30936" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ServiceOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_b42bcb29-9f9a-44b4-913d-85b2b0aeeaca" xlink:to="loc_us-gaap_ServiceOtherMember_91b5e31a-4cf3-43d0-ad3d-485743b30936" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_SoftwareMember_8d4d384d-5b5f-466b-8401-30ba5729bf3b" xlink:href="cvlt-20210930.xsd#cvlt_SoftwareMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_b42bcb29-9f9a-44b4-913d-85b2b0aeeaca" xlink:to="loc_cvlt_SoftwareMember_8d4d384d-5b5f-466b-8401-30ba5729bf3b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_32968044-e395-4a3d-9154-ebbf353d9286" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_469dc908-38e0-4122-8a5e-295a138ce9a6" xlink:to="loc_srt_StatementGeographicalAxis_32968044-e395-4a3d-9154-ebbf353d9286" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_32968044-e395-4a3d-9154-ebbf353d9286_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_32968044-e395-4a3d-9154-ebbf353d9286" xlink:to="loc_srt_SegmentGeographicalDomain_32968044-e395-4a3d-9154-ebbf353d9286_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_1dc89ba8-0e32-4c20-b598-b753e51dc2b8" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_32968044-e395-4a3d-9154-ebbf353d9286" xlink:to="loc_srt_SegmentGeographicalDomain_1dc89ba8-0e32-4c20-b598-b753e51dc2b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AmericasMember_e1245b5d-8334-4515-af21-6c8440f926a9" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AmericasMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_1dc89ba8-0e32-4c20-b598-b753e51dc2b8" xlink:to="loc_srt_AmericasMember_e1245b5d-8334-4515-af21-6c8440f926a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EMEAMember_2ce9feb2-e2c0-4d6f-9006-fac441adace8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EMEAMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_1dc89ba8-0e32-4c20-b598-b753e51dc2b8" xlink:to="loc_us-gaap_EMEAMember_2ce9feb2-e2c0-4d6f-9006-fac441adace8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaPacificMember_64278f78-c49b-415f-a1c8-c261d5199df7" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_AsiaPacificMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_1dc89ba8-0e32-4c20-b598-b753e51dc2b8" xlink:to="loc_srt_AsiaPacificMember_64278f78-c49b-415f-a1c8-c261d5199df7" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/RevenueOpeningandClosingBalancesofAccountsReceivablesUnbilledReceivablesandDeferredRevenuesDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#RevenueOpeningandClosingBalancesofAccountsReceivablesUnbilledReceivablesandDeferredRevenuesDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/RevenueOpeningandClosingBalancesofAccountsReceivablesUnbilledReceivablesandDeferredRevenuesDetails" xlink:type="extended" id="i2e9c9e4384cb47a194d750f138826418_RevenueOpeningandClosingBalancesofAccountsReceivablesUnbilledReceivablesandDeferredRevenuesDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_a5677f8e-1d03-43b1-8914-6983bb0f694f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsNotesAndLoansReceivableLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_AccountsReceivableRollForward_2db1868a-d112-4e12-bf8b-a7e1c3771012" xlink:href="cvlt-20210930.xsd#cvlt_AccountsReceivableRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_a5677f8e-1d03-43b1-8914-6983bb0f694f" xlink:to="loc_cvlt_AccountsReceivableRollForward_2db1868a-d112-4e12-bf8b-a7e1c3771012" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNet_7e73e214-7ac1-4602-be31-5682242431d8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cvlt_AccountsReceivableRollForward_2db1868a-d112-4e12-bf8b-a7e1c3771012" xlink:to="loc_us-gaap_AccountsReceivableNet_7e73e214-7ac1-4602-be31-5682242431d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_1532718c-2e99-44e8-8ac2-03bbe4ac4097" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cvlt_AccountsReceivableRollForward_2db1868a-d112-4e12-bf8b-a7e1c3771012" xlink:to="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_1532718c-2e99-44e8-8ac2-03bbe4ac4097" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableNet_31d498b6-df61-4678-bc5b-c7bf4abfa658" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountsReceivableNet"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ContractWithCustomerAssetNetCurrentRollForward_4f5504b9-d3d0-4802-b219-5052c184e24a" xlink:href="cvlt-20210930.xsd#cvlt_ContractWithCustomerAssetNetCurrentRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_a5677f8e-1d03-43b1-8914-6983bb0f694f" xlink:to="loc_cvlt_ContractWithCustomerAssetNetCurrentRollForward_4f5504b9-d3d0-4802-b219-5052c184e24a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetCurrent_53432551-016c-42e5-8bd9-a036293f096c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerAssetNetCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cvlt_ContractWithCustomerAssetNetCurrentRollForward_4f5504b9-d3d0-4802-b219-5052c184e24a" xlink:to="loc_us-gaap_ContractWithCustomerAssetNetCurrent_53432551-016c-42e5-8bd9-a036293f096c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ContractWithCustomerAssetNetCurrentIncreaseDecrease_08cdd042-9ef1-4c3e-ac58-99e280276bc9" xlink:href="cvlt-20210930.xsd#cvlt_ContractWithCustomerAssetNetCurrentIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cvlt_ContractWithCustomerAssetNetCurrentRollForward_4f5504b9-d3d0-4802-b219-5052c184e24a" xlink:to="loc_cvlt_ContractWithCustomerAssetNetCurrentIncreaseDecrease_08cdd042-9ef1-4c3e-ac58-99e280276bc9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetCurrent_9d324401-6da3-4909-aced-584358b9c37f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerAssetNetCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ContractWithCustomerAssetNetNoncurrentRollForward_1642ba1a-305b-4de7-ac48-916fb6118bc4" xlink:href="cvlt-20210930.xsd#cvlt_ContractWithCustomerAssetNetNoncurrentRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_a5677f8e-1d03-43b1-8914-6983bb0f694f" xlink:to="loc_cvlt_ContractWithCustomerAssetNetNoncurrentRollForward_1642ba1a-305b-4de7-ac48-916fb6118bc4" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent_02b8eb4f-f41b-42bf-a8b8-fe041011d58f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerAssetNetNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cvlt_ContractWithCustomerAssetNetNoncurrentRollForward_1642ba1a-305b-4de7-ac48-916fb6118bc4" xlink:to="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent_02b8eb4f-f41b-42bf-a8b8-fe041011d58f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ContractWithCustomerAssetNetNoncurrentIncreaseDecrease_684fb055-1705-4454-836c-d93857f7dce2" xlink:href="cvlt-20210930.xsd#cvlt_ContractWithCustomerAssetNetNoncurrentIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cvlt_ContractWithCustomerAssetNetNoncurrentRollForward_1642ba1a-305b-4de7-ac48-916fb6118bc4" xlink:to="loc_cvlt_ContractWithCustomerAssetNetNoncurrentIncreaseDecrease_684fb055-1705-4454-836c-d93857f7dce2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNetNoncurrent_664315e7-cd71-409f-abe2-da2a7e8c66d7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerAssetNetNoncurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ContractWithCustomerLiabilityCurrentRollForward_a7014161-a28e-4856-8722-2912f8885201" xlink:href="cvlt-20210930.xsd#cvlt_ContractWithCustomerLiabilityCurrentRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_a5677f8e-1d03-43b1-8914-6983bb0f694f" xlink:to="loc_cvlt_ContractWithCustomerLiabilityCurrentRollForward_a7014161-a28e-4856-8722-2912f8885201" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_0f5c3c26-47bb-416d-8dda-087a086a0541" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cvlt_ContractWithCustomerLiabilityCurrentRollForward_a7014161-a28e-4856-8722-2912f8885201" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityCurrent_0f5c3c26-47bb-416d-8dda-087a086a0541" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ContractWithCustomerLiabilityCurrentIncreaseDecrease_d82e9dca-86ac-4c88-8a6b-6c6e3efe33f1" xlink:href="cvlt-20210930.xsd#cvlt_ContractWithCustomerLiabilityCurrentIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cvlt_ContractWithCustomerLiabilityCurrentRollForward_a7014161-a28e-4856-8722-2912f8885201" xlink:to="loc_cvlt_ContractWithCustomerLiabilityCurrentIncreaseDecrease_d82e9dca-86ac-4c88-8a6b-6c6e3efe33f1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityCurrent_a0f3737d-92e6-4ad6-89a7-c48ca9c39140" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityCurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ContractWithCustomerLiabilityNoncurrentRollForward_239587bd-f129-443a-8080-de6a328f7ae8" xlink:href="cvlt-20210930.xsd#cvlt_ContractWithCustomerLiabilityNoncurrentRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_a5677f8e-1d03-43b1-8914-6983bb0f694f" xlink:to="loc_cvlt_ContractWithCustomerLiabilityNoncurrentRollForward_239587bd-f129-443a-8080-de6a328f7ae8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_77845326-52b3-4409-81e2-9b3a62b2c849" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cvlt_ContractWithCustomerLiabilityNoncurrentRollForward_239587bd-f129-443a-8080-de6a328f7ae8" xlink:to="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_77845326-52b3-4409-81e2-9b3a62b2c849" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ContractWithCustomerLiabilityNoncurrentIncreaseDecrease_e5ccdf3c-eebe-49b3-8408-be2d5b94aecf" xlink:href="cvlt-20210930.xsd#cvlt_ContractWithCustomerLiabilityNoncurrentIncreaseDecrease"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_cvlt_ContractWithCustomerLiabilityNoncurrentRollForward_239587bd-f129-443a-8080-de6a328f7ae8" xlink:to="loc_cvlt_ContractWithCustomerLiabilityNoncurrentIncreaseDecrease_e5ccdf3c-eebe-49b3-8408-be2d5b94aecf" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiabilityNoncurrent_6359a191-d471-47d8-9504-dad4a42c546c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractWithCustomerLiabilityNoncurrent"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_09d8dd62-9ba8-4172-ac3b-aa0eda21c99a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccountsNotesAndLoansReceivableLineItems_a5677f8e-1d03-43b1-8914-6983bb0f694f" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_09d8dd62-9ba8-4172-ac3b-aa0eda21c99a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_ad54af9a-d4b2-4fe1-a5bb-fb4503e91f28" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_09d8dd62-9ba8-4172-ac3b-aa0eda21c99a" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_ad54af9a-d4b2-4fe1-a5bb-fb4503e91f28" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_ad54af9a-d4b2-4fe1-a5bb-fb4503e91f28_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_ad54af9a-d4b2-4fe1-a5bb-fb4503e91f28" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_ad54af9a-d4b2-4fe1-a5bb-fb4503e91f28_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_ff074ba3-4cc6-48a5-a6be-cc690f36e55e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_ad54af9a-d4b2-4fe1-a5bb-fb4503e91f28" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_ff074ba3-4cc6-48a5-a6be-cc690f36e55e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TradeAccountsReceivableMember_b510c4ed-79a2-434e-b53b-ff1910061b95" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TradeAccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_ff074ba3-4cc6-48a5-a6be-cc690f36e55e" xlink:to="loc_us-gaap_TradeAccountsReceivableMember_b510c4ed-79a2-434e-b53b-ff1910061b95" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherAssetsMember_968953d5-0ef0-4e59-add2-5957184dbbea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_ff074ba3-4cc6-48a5-a6be-cc690f36e55e" xlink:to="loc_us-gaap_OtherAssetsMember_968953d5-0ef0-4e59-add2-5957184dbbea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_DeferredRevenueCurrentMember_2ed54d69-37e0-4dda-89d9-544ce89120c3" xlink:href="cvlt-20210930.xsd#cvlt_DeferredRevenueCurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_ff074ba3-4cc6-48a5-a6be-cc690f36e55e" xlink:to="loc_cvlt_DeferredRevenueCurrentMember_2ed54d69-37e0-4dda-89d9-544ce89120c3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_DeferredRevenueNoncurrentMember_0f1c05fd-cfe6-4712-a21d-7e3fd9986c5f" xlink:href="cvlt-20210930.xsd#cvlt_DeferredRevenueNoncurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_ff074ba3-4cc6-48a5-a6be-cc690f36e55e" xlink:to="loc_cvlt_DeferredRevenueNoncurrentMember_0f1c05fd-cfe6-4712-a21d-7e3fd9986c5f" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/StockPlansStockBasedCompensationExpenseDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#StockPlansStockBasedCompensationExpenseDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/StockPlansStockBasedCompensationExpenseDetails" xlink:type="extended" id="iea02034b9b2440e2bb3ead818f79db91_StockPlansStockBasedCompensationExpenseDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_2ccc5c1d-5300-4149-91d3-72b163487e8a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_39c04de6-6d67-45a5-8aee-fe92a3fd774d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_2ccc5c1d-5300-4149-91d3-72b163487e8a" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_39c04de6-6d67-45a5-8aee-fe92a3fd774d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_907a2d2b-7c47-4594-b7e0-09d4bfd3ab46" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsLineItems_2ccc5c1d-5300-4149-91d3-72b163487e8a" xlink:to="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_907a2d2b-7c47-4594-b7e0-09d4bfd3ab46" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_c0548f75-b09d-4142-badc-c9d2270280cf" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfEmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsTable_907a2d2b-7c47-4594-b7e0-09d4bfd3ab46" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_c0548f75-b09d-4142-badc-c9d2270280cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_c0548f75-b09d-4142-badc-c9d2270280cf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_c0548f75-b09d-4142-badc-c9d2270280cf" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_c0548f75-b09d-4142-badc-c9d2270280cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_36b12a23-6399-4545-929b-bca98c07931c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_c0548f75-b09d-4142-badc-c9d2270280cf" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_36b12a23-6399-4545-929b-bca98c07931c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_CostOfServicesRevenueMember_07f85c68-5e98-4f2a-98e3-99b87e6a98d6" xlink:href="cvlt-20210930.xsd#cvlt_CostOfServicesRevenueMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_36b12a23-6399-4545-929b-bca98c07931c" xlink:to="loc_cvlt_CostOfServicesRevenueMember_07f85c68-5e98-4f2a-98e3-99b87e6a98d6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingAndMarketingExpenseMember_28d421c9-af4c-437b-a9bb-733b7c500139" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SellingAndMarketingExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_36b12a23-6399-4545-929b-bca98c07931c" xlink:to="loc_us-gaap_SellingAndMarketingExpenseMember_28d421c9-af4c-437b-a9bb-733b7c500139" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ResearchAndDevelopmentExpenseMember_c84b145d-db1c-4710-aabd-85fe75d710ab" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ResearchAndDevelopmentExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_36b12a23-6399-4545-929b-bca98c07931c" xlink:to="loc_us-gaap_ResearchAndDevelopmentExpenseMember_c84b145d-db1c-4710-aabd-85fe75d710ab" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GeneralAndAdministrativeExpenseMember_ed6f65ad-cb1b-4ab8-89ba-77fa9008b8a0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GeneralAndAdministrativeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_36b12a23-6399-4545-929b-bca98c07931c" xlink:to="loc_us-gaap_GeneralAndAdministrativeExpenseMember_ed6f65ad-cb1b-4ab8-89ba-77fa9008b8a0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringChargesMember_ee91b29e-2cbf-470b-b43d-8113d4db96af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestructuringChargesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_36b12a23-6399-4545-929b-bca98c07931c" xlink:to="loc_us-gaap_RestructuringChargesMember_ee91b29e-2cbf-470b-b43d-8113d4db96af" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/StockPlansAdditionalInformationDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#StockPlansAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/StockPlansAdditionalInformationDetails" xlink:type="extended" id="i13a6a5319a144c7bb356798838a0db02_StockPlansAdditionalInformationDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_10438b34-426d-4bff-a021-034576f3ffb6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_e8be884a-de57-4a72-8b29-0aca7ed5f1b4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_10438b34-426d-4bff-a021-034576f3ffb6" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_e8be884a-de57-4a72-8b29-0aca7ed5f1b4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_9f3076d8-a696-422b-8c39-4d162d311c51" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_10438b34-426d-4bff-a021-034576f3ffb6" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_9f3076d8-a696-422b-8c39-4d162d311c51" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_61e8f1bb-fb36-4858-8bc2-138c3d213bb0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_10438b34-426d-4bff-a021-034576f3ffb6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_61e8f1bb-fb36-4858-8bc2-138c3d213bb0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_f558b0b7-cd75-498d-b575-962bda6dc57b" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_10438b34-426d-4bff-a021-034576f3ffb6" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_f558b0b7-cd75-498d-b575-962bda6dc57b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_ae013b74-a1ef-4d41-9895-b24de7071b2f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_10438b34-426d-4bff-a021-034576f3ffb6" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_ae013b74-a1ef-4d41-9895-b24de7071b2f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_826a5627-afa4-4821-9033-484e98a97479" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_ae013b74-a1ef-4d41-9895-b24de7071b2f" xlink:to="loc_us-gaap_AwardTypeAxis_826a5627-afa4-4821-9033-484e98a97479" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_826a5627-afa4-4821-9033-484e98a97479_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_826a5627-afa4-4821-9033-484e98a97479" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_826a5627-afa4-4821-9033-484e98a97479_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_97c42a05-1aac-453c-983b-ed1d82c39905" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_826a5627-afa4-4821-9033-484e98a97479" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_97c42a05-1aac-453c-983b-ed1d82c39905" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_31682777-2f2e-40a0-8608-c83d653cf574" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_97c42a05-1aac-453c-983b-ed1d82c39905" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_31682777-2f2e-40a0-8608-c83d653cf574" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/StockPlansRestrictedStockUnitsDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#StockPlansRestrictedStockUnitsDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/StockPlansRestrictedStockUnitsDetails" xlink:type="extended" id="i87d105219dff4dcd96c26fd6cea51b56_StockPlansRestrictedStockUnitsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_459743ea-38d8-4540-8dd7-82f7e9bd91c8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d609e96e-6d02-4919-8549-f9c98e729766" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_459743ea-38d8-4540-8dd7-82f7e9bd91c8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d609e96e-6d02-4919-8549-f9c98e729766" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_65c7e4f3-9cb2-42ff-8862-0298b544d119" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d609e96e-6d02-4919-8549-f9c98e729766" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_65c7e4f3-9cb2-42ff-8862-0298b544d119" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_47820c85-97b3-410d-84dc-29dbcb97b83d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d609e96e-6d02-4919-8549-f9c98e729766" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_47820c85-97b3-410d-84dc-29dbcb97b83d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_15eee9a0-f4a5-47a4-ba1d-11b4334102b8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d609e96e-6d02-4919-8549-f9c98e729766" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_15eee9a0-f4a5-47a4-ba1d-11b4334102b8" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_bb1323e9-7228-47c6-a923-dda23f48a2b2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_d609e96e-6d02-4919-8549-f9c98e729766" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_bb1323e9-7228-47c6-a923-dda23f48a2b2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_a4ee5a29-ca18-49ae-894b-43423466a25f" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b7c3313d-8699-4e88-bdfc-fb38eaaa91d0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_459743ea-38d8-4540-8dd7-82f7e9bd91c8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b7c3313d-8699-4e88-bdfc-fb38eaaa91d0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_1e8cf1b9-b88a-414f-b12b-78dd533973ed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b7c3313d-8699-4e88-bdfc-fb38eaaa91d0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_1e8cf1b9-b88a-414f-b12b-78dd533973ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_1b888e0c-5582-4433-8c84-629a852a8eef" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b7c3313d-8699-4e88-bdfc-fb38eaaa91d0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_1b888e0c-5582-4433-8c84-629a852a8eef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_0119967f-3062-40d1-869c-91e0f28b26b6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b7c3313d-8699-4e88-bdfc-fb38eaaa91d0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_0119967f-3062-40d1-869c-91e0f28b26b6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_f4dca6aa-7fbd-4ebe-8b48-591834ca35ea" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_b7c3313d-8699-4e88-bdfc-fb38eaaa91d0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_f4dca6aa-7fbd-4ebe-8b48-591834ca35ea" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_f93d3d18-9221-4346-a434-ee1dfa10546c" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_39964053-9d4f-4f32-8331-5984731b1362" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_459743ea-38d8-4540-8dd7-82f7e9bd91c8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_39964053-9d4f-4f32-8331-5984731b1362" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_bac3e9ca-ca30-4412-b664-56f64cbf1dbc" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_39964053-9d4f-4f32-8331-5984731b1362" xlink:to="loc_us-gaap_AwardTypeAxis_bac3e9ca-ca30-4412-b664-56f64cbf1dbc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_bac3e9ca-ca30-4412-b664-56f64cbf1dbc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_bac3e9ca-ca30-4412-b664-56f64cbf1dbc" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_bac3e9ca-ca30-4412-b664-56f64cbf1dbc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a2e77240-76f3-4bdb-9102-dfc25bb6ffd5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_bac3e9ca-ca30-4412-b664-56f64cbf1dbc" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a2e77240-76f3-4bdb-9102-dfc25bb6ffd5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_5b4b4c5d-f69e-45de-9ded-d91c233f241a" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a2e77240-76f3-4bdb-9102-dfc25bb6ffd5" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_5b4b4c5d-f69e-45de-9ded-d91c233f241a" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/StockPlansPerformanceBasedAwardsDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#StockPlansPerformanceBasedAwardsDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/StockPlansPerformanceBasedAwardsDetails" xlink:type="extended" id="i490be27065e34d62b4b0ff8c3051af79_StockPlansPerformanceBasedAwardsDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f73d50a4-8907-4bf8-bc61-38dff981dcc8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_616f337f-6b6e-4fc6-915b-e5df2780b72e" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f73d50a4-8907-4bf8-bc61-38dff981dcc8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_616f337f-6b6e-4fc6-915b-e5df2780b72e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_e4fe230b-3168-4b70-925d-40a31c46df26" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f73d50a4-8907-4bf8-bc61-38dff981dcc8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_e4fe230b-3168-4b70-925d-40a31c46df26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPotentialToVestPercent_567803cb-3ae4-492c-a77e-2dcf16b7064e" xlink:href="cvlt-20210930.xsd#cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPotentialToVestPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f73d50a4-8907-4bf8-bc61-38dff981dcc8" xlink:to="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPotentialToVestPercent_567803cb-3ae4-492c-a77e-2dcf16b7064e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_dcad00b2-9c1f-417a-892c-16200b6047f7" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_f73d50a4-8907-4bf8-bc61-38dff981dcc8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_dcad00b2-9c1f-417a-892c-16200b6047f7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_28fbc281-2794-407e-be7f-dc85f4da3822" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_dcad00b2-9c1f-417a-892c-16200b6047f7" xlink:to="loc_us-gaap_AwardTypeAxis_28fbc281-2794-407e-be7f-dc85f4da3822" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_28fbc281-2794-407e-be7f-dc85f4da3822_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_28fbc281-2794-407e-be7f-dc85f4da3822" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_28fbc281-2794-407e-be7f-dc85f4da3822_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_11088982-c88b-4ae5-9b6d-5ff76d1bb8cb" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_28fbc281-2794-407e-be7f-dc85f4da3822" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_11088982-c88b-4ae5-9b6d-5ff76d1bb8cb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_PerformanceRestrictedStockUnitsMember_33419e6e-b4b3-4aee-b2e3-0e0398e3b85c" xlink:href="cvlt-20210930.xsd#cvlt_PerformanceRestrictedStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_11088982-c88b-4ae5-9b6d-5ff76d1bb8cb" xlink:to="loc_cvlt_PerformanceRestrictedStockUnitsMember_33419e6e-b4b3-4aee-b2e3-0e0398e3b85c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_a53ab3a7-a2ca-4a63-acb3-607dceefdbda" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_dcad00b2-9c1f-417a-892c-16200b6047f7" xlink:to="loc_srt_RangeAxis_a53ab3a7-a2ca-4a63-acb3-607dceefdbda" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_a53ab3a7-a2ca-4a63-acb3-607dceefdbda_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_a53ab3a7-a2ca-4a63-acb3-607dceefdbda" xlink:to="loc_srt_RangeMember_a53ab3a7-a2ca-4a63-acb3-607dceefdbda_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_94aecbec-8997-4a04-8d0c-cb99c9548988" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_a53ab3a7-a2ca-4a63-acb3-607dceefdbda" xlink:to="loc_srt_RangeMember_94aecbec-8997-4a04-8d0c-cb99c9548988" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_eb2a5335-273d-4fe0-8e91-90922bac8b8d" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_94aecbec-8997-4a04-8d0c-cb99c9548988" xlink:to="loc_srt_MaximumMember_eb2a5335-273d-4fe0-8e91-90922bac8b8d" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/StockPlansAwardswithaMarketConditionDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#StockPlansAwardswithaMarketConditionDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/StockPlansAwardswithaMarketConditionDetails" xlink:type="extended" id="ifa440e0cc26c4b3bac8d9944e83e629c_StockPlansAwardswithaMarketConditionDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_13a56b10-f532-4037-bae5-5ede5a357aa5" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_2b8952f4-c2ca-461d-8932-411583ec0991" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_13a56b10-f532-4037-bae5-5ede5a357aa5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_2b8952f4-c2ca-461d-8932-411583ec0991" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_58435131-210c-437f-8704-705b181e2c17" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_13a56b10-f532-4037-bae5-5ede5a357aa5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_58435131-210c-437f-8704-705b181e2c17" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAnnualTranches_dc4eec4a-9d5f-4d2e-8c79-7a23601bcf08" xlink:href="cvlt-20210930.xsd#cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAnnualTranches"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_13a56b10-f532-4037-bae5-5ede5a357aa5" xlink:to="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAnnualTranches_dc4eec4a-9d5f-4d2e-8c79-7a23601bcf08" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPotentialToVestPercent_6898eb4d-f056-4c02-a83a-46e520e384d7" xlink:href="cvlt-20210930.xsd#cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPotentialToVestPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_13a56b10-f532-4037-bae5-5ede5a357aa5" xlink:to="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPotentialToVestPercent_6898eb4d-f056-4c02-a83a-46e520e384d7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPotentialToVestShares_882db350-4d4f-4cd1-a2b6-f96b3f2f1cfb" xlink:href="cvlt-20210930.xsd#cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPotentialToVestShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_13a56b10-f532-4037-bae5-5ede5a357aa5" xlink:to="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPotentialToVestShares_882db350-4d4f-4cd1-a2b6-f96b3f2f1cfb" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_78863971-c406-45db-94f1-2d6d5179c25d" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_13a56b10-f532-4037-bae5-5ede5a357aa5" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_78863971-c406-45db-94f1-2d6d5179c25d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b6da3c73-a9e6-46fc-a760-99f883ea5a16" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_13a56b10-f532-4037-bae5-5ede5a357aa5" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b6da3c73-a9e6-46fc-a760-99f883ea5a16" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_25d9ec6b-152b-46f8-ad81-2d214f675bf2" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b6da3c73-a9e6-46fc-a760-99f883ea5a16" xlink:to="loc_us-gaap_AwardTypeAxis_25d9ec6b-152b-46f8-ad81-2d214f675bf2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_25d9ec6b-152b-46f8-ad81-2d214f675bf2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_25d9ec6b-152b-46f8-ad81-2d214f675bf2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_25d9ec6b-152b-46f8-ad81-2d214f675bf2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_68f07588-1704-4fea-a3ed-3d985e4b08af" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_25d9ec6b-152b-46f8-ad81-2d214f675bf2" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_68f07588-1704-4fea-a3ed-3d985e4b08af" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_cd7d41ca-a29c-4363-9059-bd65c0c70449" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_68f07588-1704-4fea-a3ed-3d985e4b08af" xlink:to="loc_us-gaap_PerformanceSharesMember_cd7d41ca-a29c-4363-9059-bd65c0c70449" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_b551ab58-0e94-4293-9cff-98492a4306e6" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b6da3c73-a9e6-46fc-a760-99f883ea5a16" xlink:to="loc_srt_RangeAxis_b551ab58-0e94-4293-9cff-98492a4306e6" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_b551ab58-0e94-4293-9cff-98492a4306e6_default" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_b551ab58-0e94-4293-9cff-98492a4306e6" xlink:to="loc_srt_RangeMember_b551ab58-0e94-4293-9cff-98492a4306e6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_c784840f-64b3-49e6-9915-8ea78ff731f5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_b551ab58-0e94-4293-9cff-98492a4306e6" xlink:to="loc_srt_RangeMember_c784840f-64b3-49e6-9915-8ea78ff731f5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_70d177c1-591a-4776-b210-f29b0c7595d5" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_c784840f-64b3-49e6-9915-8ea78ff731f5" xlink:to="loc_srt_MaximumMember_70d177c1-591a-4776-b210-f29b0c7595d5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.commvault.com/role/StockPlansEmployeeStockPurchaseplanDetails" xlink:type="simple" xlink:href="cvlt-20210930.xsd#StockPlansEmployeeStockPurchaseplanDetails"/>
  <link:definitionLink xlink:role="http://www.commvault.com/role/StockPlansEmployeeStockPurchaseplanDetails" xlink:type="extended" id="i4aa089aff79f4d078dc26c2524353718_StockPlansEmployeeStockPurchaseplanDetails">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_29a4913d-dbd9-4d87-b186-560c6f1219f8" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_4d124a82-244a-4860-8ea8-32456c0edde6" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_29a4913d-dbd9-4d87-b186-560c6f1219f8" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_4d124a82-244a-4860-8ea8-32456c0edde6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfferingPeriod_d87163de-e68b-4909-a046-b11f7d8084b4" xlink:href="cvlt-20210930.xsd#cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfferingPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_29a4913d-dbd9-4d87-b186-560c6f1219f8" xlink:to="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfferingPeriod_d87163de-e68b-4909-a046-b11f7d8084b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_955fc197-99e8-4c55-b2e4-ec93a81ead48" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_29a4913d-dbd9-4d87-b186-560c6f1219f8" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumEmployeeSubscriptionRate_955fc197-99e8-4c55-b2e4-ec93a81ead48" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumAnnualPurchasesPerEmployeeAmount_e9a8faf3-77fa-4d2d-b837-40b355735941" xlink:href="cvlt-20210930.xsd#cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumAnnualPurchasesPerEmployeeAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_29a4913d-dbd9-4d87-b186-560c6f1219f8" xlink:to="loc_cvlt_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumAnnualPurchasesPerEmployeeAmount_e9a8faf3-77fa-4d2d-b837-40b355735941" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_2e809307-63c1-4cc6-bd9a-80769cf79346" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_29a4913d-dbd9-4d87-b186-560c6f1219f8" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_2e809307-63c1-4cc6-bd9a-80769cf79346" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromStockPlans_80f77336-3645-4277-93d9-6011d9d836c9" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromStockPlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_29a4913d-dbd9-4d87-b186-560c6f1219f8" xlink:to="loc_us-gaap_ProceedsFromStockPlans_80f77336-3645-4277-93d9-6011d9d836c9" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_eeb06ec9-ef00-471a-9c4c-24f9407c06fd" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_29a4913d-dbd9-4d87-b186-560c6f1219f8" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_eeb06ec9-ef00-471a-9c4c-24f9407c06fd" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_6514428f-14c0-4b4a-8408-33befafcdb16" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_29a4913d-dbd9-4d87-b186-560c6f1219f8" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_6514428f-14c0-4b4a-8408-33befafcdb16" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_40546eb6-0bea-4bf4-a02c-6a80f203a812" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_29a4913d-dbd9-4d87-b186-560c6f1219f8" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_40546eb6-0bea-4bf4-a02c-6a80f203a812" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_664c9c3d-12e7-42bb-a00b-57f100351489" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_40546eb6-0bea-4bf4-a02c-6a80f203a812" xlink:to="loc_us-gaap_AwardTypeAxis_664c9c3d-12e7-42bb-a00b-57f100351489" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_664c9c3d-12e7-42bb-a00b-57f100351489_default" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_664c9c3d-12e7-42bb-a00b-57f100351489" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_664c9c3d-12e7-42bb-a00b-57f100351489_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a5726b6d-182d-460f-897b-08653bd030a0" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_664c9c3d-12e7-42bb-a00b-57f100351489" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a5726b6d-182d-460f-897b-08653bd030a0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember_07c608a5-f07f-4b56-b283-8ace1f8c1ab4" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_a5726b6d-182d-460f-897b-08653bd030a0" xlink:to="loc_us-gaap_EmployeeStockMember_07c608a5-f07f-4b56-b283-8ace1f8c1ab4" xlink:type="arc" order="0"/>
  </link:definitionLink>
</link:linkbase>
