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

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2026 Workiva-->
<!--r:01a01027-9397-76ac-877e-5b11892e83df,g:18c2da9b-2a53-419f-b91e-79ba323b352f-->
<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.bioscrip.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" xlink:type="simple" xlink:href="bios-20260930.xsd#UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/UNAUDITEDCONDENSEDCONSOLIDATEDSTATEMENTSOFSTOCKHOLDERSEQUITY" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_01a01027-9449-7486-be08-7274980d4bb2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_01a01027-9449-78a4-acca-ed2d8ffb9bd0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_01a01027-9449-7486-be08-7274980d4bb2" xlink:to="loc_us-gaap_StatementTable_01a01027-9449-78a4-acca-ed2d8ffb9bd0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_01a01027-9449-757a-8d82-5405b46445f3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_01a01027-9449-78a4-acca-ed2d8ffb9bd0" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_01a01027-9449-757a-8d82-5405b46445f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a01027-9449-757a-8d82-5405b46445f3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a01027-9449-757a-8d82-5405b46445f3" xlink:to="loc_us-gaap_EquityComponentDomain_01a01027-9449-757a-8d82-5405b46445f3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a01027-9449-78de-a19b-2b2fce59f6c0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a01027-9449-757a-8d82-5405b46445f3" xlink:to="loc_us-gaap_EquityComponentDomain_01a01027-9449-78de-a19b-2b2fce59f6c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockMember_01a01027-9449-768f-9ecb-e6598b9ec0ad" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a01027-9449-78de-a19b-2b2fce59f6c0" xlink:to="loc_us-gaap_PreferredStockMember_01a01027-9449-768f-9ecb-e6598b9ec0ad" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_01a01027-9449-79de-8e21-21d578669fd4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a01027-9449-78de-a19b-2b2fce59f6c0" xlink:to="loc_us-gaap_CommonStockMember_01a01027-9449-79de-8e21-21d578669fd4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_01a01027-9449-7d74-9838-c80c96667b59" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a01027-9449-78de-a19b-2b2fce59f6c0" xlink:to="loc_us-gaap_TreasuryStockCommonMember_01a01027-9449-7d74-9838-c80c96667b59" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_01a01027-9449-761e-a2ce-b271787b80e4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a01027-9449-78de-a19b-2b2fce59f6c0" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_01a01027-9449-761e-a2ce-b271787b80e4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_01a01027-9449-7d81-83ef-bc01045f207d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a01027-9449-78de-a19b-2b2fce59f6c0" xlink:to="loc_us-gaap_RetainedEarningsMember_01a01027-9449-7d81-83ef-bc01045f207d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_01a01027-9449-7d84-bdf6-6106a01e280e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a01027-9449-78de-a19b-2b2fce59f6c0" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_01a01027-9449-7d84-bdf6-6106a01e280e" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-9449-722f-8b5e-e3ffd4f920b7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_01a01027-9449-7486-be08-7274980d4bb2" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-9449-722f-8b5e-e3ffd4f920b7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_01a01027-9449-76d4-804d-b4e594047814" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-9449-722f-8b5e-e3ffd4f920b7" xlink:to="loc_us-gaap_StockholdersEquity_01a01027-9449-76d4-804d-b4e594047814" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_StockIssuedValueRestrictedStockStockOptionsExercisedAndTaxWithholdings_01a01027-9449-7b4c-98d0-2b876d715bab" xlink:href="bios-20260930.xsd#bios_StockIssuedValueRestrictedStockStockOptionsExercisedAndTaxWithholdings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-9449-722f-8b5e-e3ffd4f920b7" xlink:to="loc_bios_StockIssuedValueRestrictedStockStockOptionsExercisedAndTaxWithholdings_01a01027-9449-7b4c-98d0-2b876d715bab" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_01a01027-9449-724b-9659-d4f4b814ee63" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-9449-722f-8b5e-e3ffd4f920b7" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_01a01027-9449-724b-9659-d4f4b814ee63" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_StockRepurchasedDuringPeriodValueIncludingRelatedTaxEffects_01a01027-9449-7fb8-aa5a-22a139fc0aac" xlink:href="bios-20260930.xsd#bios_StockRepurchasedDuringPeriodValueIncludingRelatedTaxEffects"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-9449-722f-8b5e-e3ffd4f920b7" xlink:to="loc_bios_StockRepurchasedDuringPeriodValueIncludingRelatedTaxEffects_01a01027-9449-7fb8-aa5a-22a139fc0aac" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_01a01027-9449-74f2-ab4f-601f4434cabf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-9449-722f-8b5e-e3ffd4f920b7" xlink:to="loc_us-gaap_NetIncomeLoss_01a01027-9449-74f2-ab4f-601f4434cabf" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_01a01027-9449-742d-ba65-a33326454ab6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-9449-722f-8b5e-e3ffd4f920b7" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent_01a01027-9449-742d-ba65-a33326454ab6" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_01a01027-9449-7517-ad81-edb937202e35" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/NATUREOFOPERATIONSANDPRESENTATIONOFFINANCIALSTATEMENTSDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#NATUREOFOPERATIONSANDPRESENTATIONOFFINANCIALSTATEMENTSDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/NATUREOFOPERATIONSANDPRESENTATIONOFFINANCIALSTATEMENTSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-79b0-8f9b-01ac8a13facd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_01a01027-9449-7aa1-819d-5ca97e8dcf23" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-79b0-8f9b-01ac8a13facd" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_01a01027-9449-7aa1-819d-5ca97e8dcf23" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a01027-9449-7bc9-9762-48fc0be831b6" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_01a01027-9449-7aa1-819d-5ca97e8dcf23" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a01027-9449-7bc9-9762-48fc0be831b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_01a01027-9449-7bc9-9762-48fc0be831b6_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a01027-9449-7bc9-9762-48fc0be831b6" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_01a01027-9449-7bc9-9762-48fc0be831b6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_01a01027-9449-75d1-a3e1-ec61d1ba2abb" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_01a01027-9449-7bc9-9762-48fc0be831b6" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_01a01027-9449-75d1-a3e1-ec61d1ba2abb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_LegacyHealthSystemsMember_01a01027-9449-7d0e-8296-67a06d921fa3" xlink:href="bios-20260930.xsd#bios_LegacyHealthSystemsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_01a01027-9449-75d1-a3e1-ec61d1ba2abb" xlink:to="loc_bios_LegacyHealthSystemsMember_01a01027-9449-7d0e-8296-67a06d921fa3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_NumberOfServiceLocations_01a01027-9449-7754-ab82-bbc7c5bd594d" xlink:href="bios-20260930.xsd#bios_NumberOfServiceLocations"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-79b0-8f9b-01ac8a13facd" xlink:to="loc_bios_NumberOfServiceLocations_01a01027-9449-7754-ab82-bbc7c5bd594d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_NumberOfServiceLocationsIncludingAmbulatoryInfusionSuites_01a01027-9449-77f6-8523-117120461cbc" xlink:href="bios-20260930.xsd#bios_NumberOfServiceLocationsIncludingAmbulatoryInfusionSuites"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-79b0-8f9b-01ac8a13facd" xlink:to="loc_bios_NumberOfServiceLocationsIncludingAmbulatoryInfusionSuites_01a01027-9449-77f6-8523-117120461cbc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_NumberOfInfusionSitesIncludingAdvancesPractitionerCapability_01a01027-9449-70d0-8e64-f491b6074664" xlink:href="bios-20260930.xsd#bios_NumberOfInfusionSitesIncludingAdvancesPractitionerCapability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-79b0-8f9b-01ac8a13facd" xlink:to="loc_bios_NumberOfInfusionSitesIncludingAdvancesPractitionerCapability_01a01027-9449-70d0-8e64-f491b6074664" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfOperatingSegments_01a01027-9449-78ec-85b9-75eca8b4ee73" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NumberOfOperatingSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-79b0-8f9b-01ac8a13facd" xlink:to="loc_us-gaap_NumberOfOperatingSegments_01a01027-9449-78ec-85b9-75eca8b4ee73" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_01a01027-9449-7843-8167-ea824a41d6ba" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-79b0-8f9b-01ac8a13facd" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_01a01027-9449-7843-8167-ea824a41d6ba" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/SUMMARYOFSIGNIFICANTACCOUNTINGPOLICIESDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskLineItems_01a01027-9449-7cd1-a671-3345bac18c0c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTable_01a01027-9449-7202-9224-00a5b59f0fa9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_01a01027-9449-7cd1-a671-3345bac18c0c" xlink:to="loc_us-gaap_ConcentrationRiskTable_01a01027-9449-7202-9224-00a5b59f0fa9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a01027-9449-7bc8-941d-fde2ae7d01b4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_01a01027-9449-7202-9224-00a5b59f0fa9" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a01027-9449-7bc8-941d-fde2ae7d01b4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a01027-9449-7bc8-941d-fde2ae7d01b4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a01027-9449-7bc8-941d-fde2ae7d01b4" xlink:to="loc_us-gaap_RelatedPartyDomain_01a01027-9449-7bc8-941d-fde2ae7d01b4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a01027-9449-7362-82fa-40df7761cb1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a01027-9449-7bc8-941d-fde2ae7d01b4" xlink:to="loc_us-gaap_RelatedPartyDomain_01a01027-9449-7362-82fa-40df7761cb1a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateJointVentureMember_01a01027-9449-7b3d-b02a-e14fe3a65c3d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateJointVentureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a01027-9449-7362-82fa-40df7761cb1a" xlink:to="loc_us-gaap_CorporateJointVentureMember_01a01027-9449-7b3d-b02a-e14fe3a65c3d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_01a01027-9449-736c-bf22-27dd1a38d29d" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_01a01027-9449-7202-9224-00a5b59f0fa9" xlink:to="loc_srt_MajorCustomersAxis_01a01027-9449-736c-bf22-27dd1a38d29d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-736c-bf22-27dd1a38d29d_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_01a01027-9449-736c-bf22-27dd1a38d29d" xlink:to="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-736c-bf22-27dd1a38d29d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-758b-b1df-2d465b891cbc" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_01a01027-9449-736c-bf22-27dd1a38d29d" xlink:to="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-758b-b1df-2d465b891cbc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_LargestPayerMember_01a01027-9449-78c2-9767-6beedd3a42a8" xlink:href="bios-20260930.xsd#bios_LargestPayerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-758b-b1df-2d465b891cbc" xlink:to="loc_bios_LargestPayerMember_01a01027-9449-78c2-9767-6beedd3a42a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_01a01027-9449-7cdc-a2f3-35091c06e1c6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_01a01027-9449-7202-9224-00a5b59f0fa9" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_01a01027-9449-7cdc-a2f3-35091c06e1c6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_01a01027-9449-7cdc-a2f3-35091c06e1c6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_01a01027-9449-7cdc-a2f3-35091c06e1c6" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_01a01027-9449-7cdc-a2f3-35091c06e1c6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_01a01027-9449-7a54-8ae9-97b1c0dbbb97" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_01a01027-9449-7cdc-a2f3-35091c06e1c6" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_01a01027-9449-7a54-8ae9-97b1c0dbbb97" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerMember_01a01027-9449-715f-beaa-0aa57d84ae15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_01a01027-9449-7a54-8ae9-97b1c0dbbb97" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerMember_01a01027-9449-715f-beaa-0aa57d84ae15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_AccountsReceivableBenchmarkMember_01a01027-9449-7523-981f-23335b65df0b" xlink:href="bios-20260930.xsd#bios_AccountsReceivableBenchmarkMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_01a01027-9449-7a54-8ae9-97b1c0dbbb97" xlink:to="loc_bios_AccountsReceivableBenchmarkMember_01a01027-9449-7523-981f-23335b65df0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfGoodsProductLineMember_01a01027-9449-7b97-ba01-b8eff1289962" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfGoodsProductLineMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_01a01027-9449-7a54-8ae9-97b1c0dbbb97" xlink:to="loc_us-gaap_CostOfGoodsProductLineMember_01a01027-9449-7b97-ba01-b8eff1289962" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_01a01027-9449-7bae-bf66-cc5c9be31606" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_01a01027-9449-7202-9224-00a5b59f0fa9" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_01a01027-9449-7bae-bf66-cc5c9be31606" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_01a01027-9449-7bae-bf66-cc5c9be31606_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_01a01027-9449-7bae-bf66-cc5c9be31606" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_01a01027-9449-7bae-bf66-cc5c9be31606_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_01a01027-9449-7664-bc2c-8f2480e554f4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_01a01027-9449-7bae-bf66-cc5c9be31606" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_01a01027-9449-7664-bc2c-8f2480e554f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_01a01027-9449-7eaa-9142-aaaf4c07e64b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_01a01027-9449-7664-bc2c-8f2480e554f4" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_01a01027-9449-7eaa-9142-aaaf4c07e64b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GovernmentContractsConcentrationRiskMember_01a01027-9449-73ac-945e-39e02cc7a4bd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_GovernmentContractsConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_01a01027-9449-7664-bc2c-8f2480e554f4" xlink:to="loc_us-gaap_GovernmentContractsConcentrationRiskMember_01a01027-9449-73ac-945e-39e02cc7a4bd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplierConcentrationRiskMember_01a01027-9449-7b42-8d71-6269b0dcc46b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SupplierConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_01a01027-9449-7664-bc2c-8f2480e554f4" xlink:to="loc_us-gaap_SupplierConcentrationRiskMember_01a01027-9449-7b42-8d71-6269b0dcc46b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis_01a01027-9449-72c5-ad69-b44a681a94e3" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_01a01027-9449-7202-9224-00a5b59f0fa9" xlink:to="loc_srt_ProductOrServiceAxis_01a01027-9449-72c5-ad69-b44a681a94e3" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_01a01027-9449-72c5-ad69-b44a681a94e3_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_01a01027-9449-72c5-ad69-b44a681a94e3" xlink:to="loc_srt_ProductsAndServicesDomain_01a01027-9449-72c5-ad69-b44a681a94e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain_01a01027-9449-70eb-b666-e11f8aa876d2" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_01a01027-9449-72c5-ad69-b44a681a94e3" xlink:to="loc_srt_ProductsAndServicesDomain_01a01027-9449-70eb-b666-e11f8aa876d2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_GovernmentHealthcareProgramsMember_01a01027-9449-79fa-93d5-03f8d69fd28d" xlink:href="bios-20260930.xsd#bios_GovernmentHealthcareProgramsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_01a01027-9449-70eb-b666-e11f8aa876d2" xlink:to="loc_bios_GovernmentHealthcareProgramsMember_01a01027-9449-79fa-93d5-03f8d69fd28d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_01a01027-9449-7492-9ba8-131f22ef2d32" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ConcentrationRiskTable_01a01027-9449-7202-9224-00a5b59f0fa9" xlink:to="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_01a01027-9449-7492-9ba8-131f22ef2d32" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_01a01027-9449-7492-9ba8-131f22ef2d32_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_01a01027-9449-7492-9ba8-131f22ef2d32" xlink:to="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_01a01027-9449-7492-9ba8-131f22ef2d32_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_01a01027-9449-7c5a-93ab-26dc5fbf4a1a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionBySupplierAxis_01a01027-9449-7492-9ba8-131f22ef2d32" xlink:to="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_01a01027-9449-7c5a-93ab-26dc5fbf4a1a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_ThreeVendorsMember_01a01f92-86f2-7931-98ae-e6f6f738e430" xlink:href="bios-20260930.xsd#bios_ThreeVendorsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_01a01027-9449-7c5a-93ab-26dc5fbf4a1a" xlink:to="loc_bios_ThreeVendorsMember_01a01f92-86f2-7931-98ae-e6f6f738e430" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_FourVendorsMember_01a01027-9449-7f53-9a52-adbeef1ece3e" xlink:href="bios-20260930.xsd#bios_FourVendorsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedGoodsAndNonemployeeServicesTransactionSupplierDomain_01a01027-9449-7c5a-93ab-26dc5fbf4a1a" xlink:to="loc_bios_FourVendorsMember_01a01027-9449-7f53-9a52-adbeef1ece3e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnbilledReceivablesCurrent_01a01027-9449-7c8e-999a-4005f24de129" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_UnbilledReceivablesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_01a01027-9449-7cd1-a671-3345bac18c0c" xlink:to="loc_us-gaap_UnbilledReceivablesCurrent_01a01027-9449-7c8e-999a-4005f24de129" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLoss_01a01027-9449-74ae-b73e-7a0a4100f982" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_01a01027-9449-7cd1-a671-3345bac18c0c" xlink:to="loc_us-gaap_ContractWithCustomerReceivableAfterAllowanceForCreditLoss_01a01027-9449-74ae-b73e-7a0a4100f982" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestments_01a01027-9449-7a2e-b960-cc2dbc3a9f5c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_01a01027-9449-7cd1-a671-3345bac18c0c" xlink:to="loc_us-gaap_EquityMethodInvestments_01a01027-9449-7a2e-b960-cc2dbc3a9f5c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_01a01027-9449-71a4-908c-79b413faea51" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_01a01027-9449-7cd1-a671-3345bac18c0c" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_01a01027-9449-71a4-908c-79b413faea51" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_01a01027-9449-78e4-ab8d-b7cd75073691" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_01a01027-9449-7cd1-a671-3345bac18c0c" xlink:to="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_01a01027-9449-78e4-ab8d-b7cd75073691" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_01a01027-9449-7536-b51c-58c0632c92a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskLineItems_01a01027-9449-7cd1-a671-3345bac18c0c" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_01a01027-9449-7536-b51c-58c0632c92a9" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/BUSINESSCOMBINATIONSAdditionalInformationDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#BUSINESSCOMBINATIONSAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/BUSINESSCOMBINATIONSAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-70f1-a339-4fdf2103c668" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_01a01027-9449-7d32-af0d-407ef4b813f5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-70f1-a339-4fdf2103c668" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_01a01027-9449-7d32-af0d-407ef4b813f5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_01a01027-9449-7cf2-a6d5-0f63582046f0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_01a01027-9449-7d32-af0d-407ef4b813f5" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_01a01027-9449-7cf2-a6d5-0f63582046f0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-9449-7cf2-a6d5-0f63582046f0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01a01027-9449-7cf2-a6d5-0f63582046f0" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-9449-7cf2-a6d5-0f63582046f0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-9449-7349-886d-2a0e223e4473" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01a01027-9449-7cf2-a6d5-0f63582046f0" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-9449-7349-886d-2a0e223e4473" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_IntramedPlusIncMember_01a01027-9449-7063-b4b8-cc898f57f429" xlink:href="bios-20260930.xsd#bios_IntramedPlusIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-9449-7349-886d-2a0e223e4473" xlink:to="loc_bios_IntramedPlusIncMember_01a01027-9449-7063-b4b8-cc898f57f429" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_01a01027-9449-7c71-9162-c9099aebe00a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-70f1-a339-4fdf2103c668" xlink:to="loc_us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired_01a01027-9449-7c71-9162-c9099aebe00a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_01a01027-9449-7a01-8e72-edbd8aad5ead" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-70f1-a339-4fdf2103c668" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_01a01027-9449-7a01-8e72-edbd8aad5ead" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/BUSINESSCOMBINATIONSScheduleofPreliminaryEstimateoftheAllocationConsiderationTransferredDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#BUSINESSCOMBINATIONSScheduleofPreliminaryEstimateoftheAllocationConsiderationTransferredDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/BUSINESSCOMBINATIONSScheduleofPreliminaryEstimateoftheAllocationConsiderationTransferredDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_01a01027-9449-7cfc-abb6-050216ae54e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_01a01027-9449-7cfc-abb6-050216ae54e7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_01a01027-9449-72fd-a522-464e3e0a539c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_01a01027-9449-7cfc-abb6-050216ae54e7" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_01a01027-9449-72fd-a522-464e3e0a539c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-9449-72fd-a522-464e3e0a539c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01a01027-9449-72fd-a522-464e3e0a539c" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-9449-72fd-a522-464e3e0a539c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-9449-7993-a95f-1e120ece5f18" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01a01027-9449-72fd-a522-464e3e0a539c" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-9449-7993-a95f-1e120ece5f18" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_IntramedPlusIncMember_01a01027-9449-778f-aa63-575c20423493" xlink:href="bios-20260930.xsd#bios_IntramedPlusIncMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-9449-7993-a95f-1e120ece5f18" xlink:to="loc_bios_IntramedPlusIncMember_01a01027-9449-778f-aa63-575c20423493" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a01027-9449-7d3b-8206-6c44038b4de2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_01a01027-9449-7cfc-abb6-050216ae54e7" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a01027-9449-7d3b-8206-6c44038b4de2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7d3b-8206-6c44038b4de2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a01027-9449-7d3b-8206-6c44038b4de2" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7d3b-8206-6c44038b4de2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7b41-90af-5b177d1050f1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a01027-9449-7d3b-8206-6c44038b4de2" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7b41-90af-5b177d1050f1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_ReferralSourcesMember_01a01027-9449-76c9-b39c-c1df6b0feadf" xlink:href="bios-20260930.xsd#bios_ReferralSourcesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7b41-90af-5b177d1050f1" xlink:to="loc_bios_ReferralSourcesMember_01a01027-9449-76c9-b39c-c1df6b0feadf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_01a01027-9449-7a3c-a460-3e2e1eb577de" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TrademarksAndTradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7b41-90af-5b177d1050f1" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_01a01027-9449-7a3c-a460-3e2e1eb577de" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_01a01027-9449-7e91-9307-1506d3f75090" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables_01a01027-9449-7e91-9307-1506d3f75090" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_01a01027-9449-78ec-b769-91a3ff7f40d7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_01a01027-9449-78ec-b769-91a3ff7f40d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_01a01027-9449-77b8-9bfb-413275d4fa46" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInventory_01a01027-9449-77b8-9bfb-413275d4fa46" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_01a01027-9449-77c2-adee-0c95e82d753a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets_01a01027-9449-77c2-adee-0c95e82d753a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndOtherLiabilities_01a01027-9449-744e-bb8a-28d5b9a127ea" xlink:href="bios-20260930.xsd#bios_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndOtherLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_bios_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAccountsPayableAndOtherLiabilities_01a01027-9449-744e-bb8a-28d5b9a127ea" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_01a01027-9449-726f-92c0-27920f78f85c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_01a01027-9449-726f-92c0-27920f78f85c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_01a01027-9449-7aa9-90fc-a397b2b196e7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_Goodwill_01a01027-9449-7aa9-90fc-a397b2b196e7" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAcquiredFromAcquisition_01a01027-9449-7668-bdc1-19fcbd079371" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAcquiredFromAcquisition"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_CashAcquiredFromAcquisition_01a01027-9449-7668-bdc1-19fcbd079371" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_01a01027-9449-7625-bc54-1f0a7267c7b9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_01a01027-9449-7625-bc54-1f0a7267c7b9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CashAcquiredFromAcquisition_01a01027-9449-7cdc-98aa-f1f8dffb547a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CashAcquiredFromAcquisition"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_01a01027-9449-7665-9875-3beffaab318b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_01a01027-9449-7665-9875-3beffaab318b" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_01a01027-9449-7be3-9233-7f5fa84a09a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_01a01027-9449-782a-b103-139cffaff809" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_01a01027-9449-7be3-9233-7f5fa84a09a9" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/REVENUEDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#REVENUEDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/REVENUEDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_01a01027-9449-7f14-ab9a-e892bd167f4b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_01a01027-9449-7098-b020-6747c2eb33d3" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_01a01027-9449-7f14-ab9a-e892bd167f4b" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_01a01027-9449-7098-b020-6747c2eb33d3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_01a01027-9449-7fd9-af6d-e30ca411e956" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_01a01027-9449-7098-b020-6747c2eb33d3" xlink:to="loc_srt_MajorCustomersAxis_01a01027-9449-7fd9-af6d-e30ca411e956" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-7fd9-af6d-e30ca411e956_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_01a01027-9449-7fd9-af6d-e30ca411e956" xlink:to="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-7fd9-af6d-e30ca411e956_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-7b3b-ac09-b20a96a0360a" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_01a01027-9449-7fd9-af6d-e30ca411e956" xlink:to="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-7b3b-ac09-b20a96a0360a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_CommercialCustomerMember_01a01027-9449-76bb-945a-81a9989d9293" xlink:href="bios-20260930.xsd#bios_CommercialCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-7b3b-ac09-b20a96a0360a" xlink:to="loc_bios_CommercialCustomerMember_01a01027-9449-76bb-945a-81a9989d9293" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_GovernmentCustomerMember_01a01027-9449-70de-9503-2a721a45b254" xlink:href="bios-20260930.xsd#bios_GovernmentCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-7b3b-ac09-b20a96a0360a" xlink:to="loc_bios_GovernmentCustomerMember_01a01027-9449-70de-9503-2a721a45b254" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_PatientCustomerMember_01a01027-9449-74a8-8723-cc0992d4d37b" xlink:href="bios-20260930.xsd#bios_PatientCustomerMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_01a01027-9449-7b3b-ac09-b20a96a0360a" xlink:to="loc_bios_PatientCustomerMember_01a01027-9449-74a8-8723-cc0992d4d37b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a01027-9449-7d94-a541-9fee61a27e2e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_01a01027-9449-7f14-ab9a-e892bd167f4b" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a01027-9449-7d94-a541-9fee61a27e2e" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/EARNINGSPERSHAREScheduleofAntidilutiveSecuritiesExcludedfromComputationofEarningsPerShareDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#EARNINGSPERSHAREScheduleofAntidilutiveSecuritiesExcludedfromComputationofEarningsPerShareDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/EARNINGSPERSHAREScheduleofAntidilutiveSecuritiesExcludedfromComputationofEarningsPerShareDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_01a01027-9449-7153-a331-b22d73ec4979" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_01a01027-9449-771e-bd7e-c75b43f7e133" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_01a01027-9449-7153-a331-b22d73ec4979" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_01a01027-9449-771e-bd7e-c75b43f7e133" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01a01027-9449-7ab8-a0c4-1b28b454097a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_01a01027-9449-771e-bd7e-c75b43f7e133" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01a01027-9449-7ab8-a0c4-1b28b454097a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a01027-9449-7ab8-a0c4-1b28b454097a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01a01027-9449-7ab8-a0c4-1b28b454097a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a01027-9449-7ab8-a0c4-1b28b454097a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a01027-9449-72f3-927d-6af7f0e0643c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_01a01027-9449-7ab8-a0c4-1b28b454097a" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a01027-9449-72f3-927d-6af7f0e0643c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockOptionMember_01a01027-9449-7bdc-92af-716aae270d2d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockOptionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a01027-9449-72f3-927d-6af7f0e0643c" xlink:to="loc_us-gaap_StockOptionMember_01a01027-9449-7bdc-92af-716aae270d2d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_RestrictedStockAwardMember_01a01027-9449-7c6a-a0a3-c95f3b2a18b8" xlink:href="bios-20260930.xsd#bios_RestrictedStockAwardMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a01027-9449-72f3-927d-6af7f0e0643c" xlink:to="loc_bios_RestrictedStockAwardMember_01a01027-9449-7c6a-a0a3-c95f3b2a18b8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_PerformanceStockUnitMember_01a01027-9449-7d17-887a-9b1f8ff9282e" xlink:href="bios-20260930.xsd#bios_PerformanceStockUnitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_01a01027-9449-72f3-927d-6af7f0e0643c" xlink:to="loc_bios_PerformanceStockUnitMember_01a01027-9449-7d17-887a-9b1f8ff9282e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_01a01027-9449-7f6d-982b-77018add3ac2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_01a01027-9449-7153-a331-b22d73ec4979" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_01a01027-9449-7f6d-982b-77018add3ac2" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/PROPERTYANDEQUIPMENTDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#PROPERTYANDEQUIPMENTDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/PROPERTYANDEQUIPMENTDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_01a01027-9449-7104-895e-fa7c930ec445" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_01a01027-9449-7104-895e-fa7c930ec445" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a01027-9449-7074-bc67-643b1119e185" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_01a01027-9449-7104-895e-fa7c930ec445" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a01027-9449-7074-bc67-643b1119e185" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7074-bc67-643b1119e185_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a01027-9449-7074-bc67-643b1119e185" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7074-bc67-643b1119e185_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a01027-9449-7074-bc67-643b1119e185" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_InfusionPumpsMember_01a01027-9449-7c4a-8c07-ed5ce19fefec" xlink:href="bios-20260930.xsd#bios_InfusionPumpsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:to="loc_bios_InfusionPumpsMember_01a01027-9449-7c4a-8c07-ed5ce19fefec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_EquipmentFurnitureAndOtherMember_01a01027-9449-7ecc-924f-b4e1fac18f2a" xlink:href="bios-20260930.xsd#bios_EquipmentFurnitureAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:to="loc_bios_EquipmentFurnitureAndOtherMember_01a01027-9449-7ecc-924f-b4e1fac18f2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_01a01027-9449-79a1-93b6-83dbb97d89a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_01a01027-9449-79a1-93b6-83dbb97d89a1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareInternallyDevelopedAndPurchasedMember_01a179a9-6a6b-783e-b813-6d3b17c3c918" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SoftwareInternallyDevelopedAndPurchasedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:to="loc_us-gaap_SoftwareInternallyDevelopedAndPurchasedMember_01a179a9-6a6b-783e-b813-6d3b17c3c918" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_AssetUnderDevelopmentMember_01a17e2c-a166-70a1-b56c-fec4f5614f75" xlink:href="bios-20260930.xsd#bios_AssetUnderDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:to="loc_bios_AssetUnderDevelopmentMember_01a17e2c-a166-70a1-b56c-fec4f5614f75" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_01a01027-9449-7355-a76e-3fd8a7cc2626" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementOfIncomeLocationBalanceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_01a01027-9449-7104-895e-fa7c930ec445" xlink:to="loc_us-gaap_StatementOfIncomeLocationBalanceAxis_01a01027-9449-7355-a76e-3fd8a7cc2626" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_01a01027-9449-7530-9d5f-9f4d222a98be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_01a01027-9449-7530-9d5f-9f4d222a98be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_01a01027-9449-73b0-82a4-aec8f2936750" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_01a01027-9449-73b0-82a4-aec8f2936750" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_01a01027-9449-7e26-973a-b6c456eacc82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_01a01027-9449-7e26-973a-b6c456eacc82" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_01a01027-9449-7f48-b39f-01051d76785a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:to="loc_us-gaap_Depreciation_01a01027-9449-7f48-b39f-01051d76785a" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/PROPERTYANDEQUIPMENTDetails_1" xlink:type="simple" xlink:href="bios-20260930.xsd#PROPERTYANDEQUIPMENTDetails_1"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/PROPERTYANDEQUIPMENTDetails_1" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_01a01027-9449-7104-895e-fa7c930ec445" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_01a01027-9449-7104-895e-fa7c930ec445" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a01027-9449-7074-bc67-643b1119e185" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_01a01027-9449-7104-895e-fa7c930ec445" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a01027-9449-7074-bc67-643b1119e185" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7074-bc67-643b1119e185_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a01027-9449-7074-bc67-643b1119e185" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7074-bc67-643b1119e185_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_01a01027-9449-7074-bc67-643b1119e185" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_InfusionPumpsMember_01a01027-9449-7c4a-8c07-ed5ce19fefec" xlink:href="bios-20260930.xsd#bios_InfusionPumpsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:to="loc_bios_InfusionPumpsMember_01a01027-9449-7c4a-8c07-ed5ce19fefec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_EquipmentFurnitureAndOtherMember_01a01027-9449-7ecc-924f-b4e1fac18f2a" xlink:href="bios-20260930.xsd#bios_EquipmentFurnitureAndOtherMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:to="loc_bios_EquipmentFurnitureAndOtherMember_01a01027-9449-7ecc-924f-b4e1fac18f2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseholdImprovementsMember_01a01027-9449-79a1-93b6-83dbb97d89a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseholdImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:to="loc_us-gaap_LeaseholdImprovementsMember_01a01027-9449-79a1-93b6-83dbb97d89a1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareInternallyDevelopedAndPurchasedMember_01a179a9-6a6b-783e-b813-6d3b17c3c918" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SoftwareInternallyDevelopedAndPurchasedMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:to="loc_us-gaap_SoftwareInternallyDevelopedAndPurchasedMember_01a179a9-6a6b-783e-b813-6d3b17c3c918" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_AssetUnderDevelopmentMember_01a17e2c-a166-70a1-b56c-fec4f5614f75" xlink:href="bios-20260930.xsd#bios_AssetUnderDevelopmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_01a01027-9449-7571-964b-3372ebd6a2cf" xlink:to="loc_bios_AssetUnderDevelopmentMember_01a17e2c-a166-70a1-b56c-fec4f5614f75" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentGross_01a01027-9449-7530-9d5f-9f4d222a98be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentGross_01a01027-9449-7530-9d5f-9f4d222a98be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_01a01027-9449-73b0-82a4-aec8f2936750" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:to="loc_us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_01a01027-9449-73b0-82a4-aec8f2936750" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentNet_01a01027-9449-7e26-973a-b6c456eacc82" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentNet_01a01027-9449-7e26-973a-b6c456eacc82" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Depreciation_01a01027-9449-7f48-b39f-01051d76785a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Depreciation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_01a01027-9449-7a32-822e-9ca2d8a0a387" xlink:to="loc_us-gaap_Depreciation_01a01027-9449-7f48-b39f-01051d76785a" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/GOODWILLANDOTHERINTANGIBLEASSETSScheduleofCarryingAmountandAccumulatedAmortizationofIntangibleAssetsDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#GOODWILLANDOTHERINTANGIBLEASSETSScheduleofCarryingAmountandAccumulatedAmortizationofIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/GOODWILLANDOTHERINTANGIBLEASSETSScheduleofCarryingAmountandAccumulatedAmortizationofIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a01027-9449-7fb2-96aa-b4772b11a9ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_01a01027-9449-7338-8889-2ec4edab3e8e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a01027-9449-7fb2-96aa-b4772b11a9ef" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_01a01027-9449-7338-8889-2ec4edab3e8e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a01027-9449-7730-975e-d99cd91ae90b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_01a01027-9449-7338-8889-2ec4edab3e8e" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a01027-9449-7730-975e-d99cd91ae90b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7730-975e-d99cd91ae90b_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a01027-9449-7730-975e-d99cd91ae90b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7730-975e-d99cd91ae90b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7c64-a2df-6c9823be4531" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_01a01027-9449-7730-975e-d99cd91ae90b" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7c64-a2df-6c9823be4531" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerListsMember_01a01027-9449-72d7-be51-32e7fb00ca6a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CustomerListsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7c64-a2df-6c9823be4531" xlink:to="loc_us-gaap_CustomerListsMember_01a01027-9449-72d7-be51-32e7fb00ca6a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksAndTradeNamesMember_01a01027-9449-7480-824e-8390d7aedf11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TrademarksAndTradeNamesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7c64-a2df-6c9823be4531" xlink:to="loc_us-gaap_TrademarksAndTradeNamesMember_01a01027-9449-7480-824e-8390d7aedf11" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember_01a01027-9449-79ac-8435-e3f99ea7ea1d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_01a01027-9449-7c64-a2df-6c9823be4531" xlink:to="loc_us-gaap_OtherIntangibleAssetsMember_01a01027-9449-79ac-8435-e3f99ea7ea1d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_01a01027-9449-718f-9797-679189efddde" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a01027-9449-7fb2-96aa-b4772b11a9ef" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_01a01027-9449-718f-9797-679189efddde" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_01a01027-9449-75e5-a37c-2a96ce85cff5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a01027-9449-7fb2-96aa-b4772b11a9ef" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_01a01027-9449-75e5-a37c-2a96ce85cff5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_01a01027-9449-7020-9ff4-a52c746d53d7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FiniteLivedIntangibleAssetsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_01a01027-9449-7fb2-96aa-b4772b11a9ef" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_01a01027-9449-7020-9ff4-a52c746d53d7" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/INDEBTEDNESSScheduleofDebtDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#INDEBTEDNESSScheduleofDebtDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/INDEBTEDNESSScheduleofDebtDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-7c25-ab8c-ac2a0c80e9a1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_01a01027-9449-7a62-8810-e708ee21cd73" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-7c25-ab8c-ac2a0c80e9a1" xlink:to="loc_us-gaap_DebtInstrumentTable_01a01027-9449-7a62-8810-e708ee21cd73" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_01a01027-9449-7d49-a562-debf0d0b8ef7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a01027-9449-7a62-8810-e708ee21cd73" xlink:to="loc_us-gaap_CreditFacilityAxis_01a01027-9449-7d49-a562-debf0d0b8ef7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_01a01027-9449-7d49-a562-debf0d0b8ef7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_01a01027-9449-7d49-a562-debf0d0b8ef7" xlink:to="loc_us-gaap_CreditFacilityDomain_01a01027-9449-7d49-a562-debf0d0b8ef7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_01a01027-9449-7c2d-960f-c7b407aa447e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_01a01027-9449-7d49-a562-debf0d0b8ef7" xlink:to="loc_us-gaap_CreditFacilityDomain_01a01027-9449-7c2d-960f-c7b407aa447e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_01a01027-9449-7a8e-a5c6-e46832993304" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_01a01027-9449-7c2d-960f-c7b407aa447e" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_01a01027-9449-7a8e-a5c6-e46832993304" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a01027-9449-7ca2-8ac2-6f6723f7d541" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a01027-9449-7a62-8810-e708ee21cd73" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a01027-9449-7ca2-8ac2-6f6723f7d541" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a01027-9449-7ca2-8ac2-6f6723f7d541_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a01027-9449-7ca2-8ac2-6f6723f7d541" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a01027-9449-7ca2-8ac2-6f6723f7d541_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a01027-9449-7cc2-b9a3-75ed3d12f523" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a01027-9449-7ca2-8ac2-6f6723f7d541" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a01027-9449-7cc2-b9a3-75ed3d12f523" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_01a01027-9449-7846-9ea9-4d450186a20c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a01027-9449-7cc2-b9a3-75ed3d12f523" xlink:to="loc_us-gaap_SeniorNotesMember_01a01027-9449-7846-9ea9-4d450186a20c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a01027-9449-7d3a-84fe-4263ec50caaf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a01027-9449-7a62-8810-e708ee21cd73" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a01027-9449-7d3a-84fe-4263ec50caaf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7d3a-84fe-4263ec50caaf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a01027-9449-7d3a-84fe-4263ec50caaf" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7d3a-84fe-4263ec50caaf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7dd4-9000-6fd4a2a23ede" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a01027-9449-7d3a-84fe-4263ec50caaf" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7dd4-9000-6fd4a2a23ede" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_FirstLienTermLoanMember_01a01027-9449-737f-b821-f99d2fa09601" xlink:href="bios-20260930.xsd#bios_FirstLienTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7dd4-9000-6fd4a2a23ede" xlink:to="loc_bios_FirstLienTermLoanMember_01a01027-9449-737f-b821-f99d2fa09601" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_SecondLienTermLoanMember_01a01027-9449-7d04-acc8-3c4d8ba5f5aa" xlink:href="bios-20260930.xsd#bios_SecondLienTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7dd4-9000-6fd4a2a23ede" xlink:to="loc_bios_SecondLienTermLoanMember_01a01027-9449-7d04-acc8-3c4d8ba5f5aa" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_01a01027-9449-7e7e-9848-695366c37127" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-7c25-ab8c-ac2a0c80e9a1" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_01a01027-9449-7e7e-9848-695366c37127" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedDiscount_01a01027-9449-7d95-ada0-17f9b61d04dc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentUnamortizedDiscount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-7c25-ab8c-ac2a0c80e9a1" xlink:to="loc_us-gaap_DebtInstrumentUnamortizedDiscount_01a01027-9449-7d95-ada0-17f9b61d04dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_01a01027-9449-79bf-aed5-0de4cf55f3c1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-7c25-ab8c-ac2a0c80e9a1" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_01a01027-9449-79bf-aed5-0de4cf55f3c1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_01a01027-9449-704f-9444-69a0beb43646" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-7c25-ab8c-ac2a0c80e9a1" xlink:to="loc_us-gaap_LongTermDebt_01a01027-9449-704f-9444-69a0beb43646" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtCurrent_01a01027-9449-79b3-a9d0-c38895156ce6" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-7c25-ab8c-ac2a0c80e9a1" xlink:to="loc_us-gaap_LongTermDebtCurrent_01a01027-9449-79b3-a9d0-c38895156ce6" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtNoncurrent_01a01027-9449-72e8-96b6-21d2e59c6146" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-7c25-ab8c-ac2a0c80e9a1" xlink:to="loc_us-gaap_LongTermDebtNoncurrent_01a01027-9449-72e8-96b6-21d2e59c6146" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/INDEBTEDNESSAdditionalInformationDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#INDEBTEDNESSAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/INDEBTEDNESSAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-742f-b861-a119bbfbe559" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_01a01027-9449-796e-941a-819f27081f71" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-742f-b861-a119bbfbe559" xlink:to="loc_us-gaap_DebtInstrumentTable_01a01027-9449-796e-941a-819f27081f71" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a01027-9449-7208-9078-6be2a6831980" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a01027-9449-796e-941a-819f27081f71" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a01027-9449-7208-9078-6be2a6831980" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7208-9078-6be2a6831980_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a01027-9449-7208-9078-6be2a6831980" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7208-9078-6be2a6831980_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7bed-bad5-f23ee6f1fc86" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a01027-9449-7208-9078-6be2a6831980" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7bed-bad5-f23ee6f1fc86" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_FirstLienCreditAgreementFifthAmendmentMember_01a01027-9449-730c-b7f4-d687e6c03294" xlink:href="bios-20260930.xsd#bios_FirstLienCreditAgreementFifthAmendmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7bed-bad5-f23ee6f1fc86" xlink:to="loc_bios_FirstLienCreditAgreementFifthAmendmentMember_01a01027-9449-730c-b7f4-d687e6c03294" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_FirstLienTermLoanMember_01a01027-9449-7c9d-8fe0-00458fea20c8" xlink:href="bios-20260930.xsd#bios_FirstLienTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7bed-bad5-f23ee6f1fc86" xlink:to="loc_bios_FirstLienTermLoanMember_01a01027-9449-7c9d-8fe0-00458fea20c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_SecondLienCreditAgreementMemberMember_01a01027-9449-7109-8e3a-98ae0fe927ef" xlink:href="bios-20260930.xsd#bios_SecondLienCreditAgreementMemberMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a01027-9449-7bed-bad5-f23ee6f1fc86" xlink:to="loc_bios_SecondLienCreditAgreementMemberMember_01a01027-9449-7109-8e3a-98ae0fe927ef" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LienCategoryAxis_01a01027-9449-7d75-a4a1-38d416c47333" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LienCategoryAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a01027-9449-796e-941a-819f27081f71" xlink:to="loc_us-gaap_LienCategoryAxis_01a01027-9449-7d75-a4a1-38d416c47333" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LienCategoryDomain_01a01027-9449-7d75-a4a1-38d416c47333_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LienCategoryDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LienCategoryAxis_01a01027-9449-7d75-a4a1-38d416c47333" xlink:to="loc_us-gaap_LienCategoryDomain_01a01027-9449-7d75-a4a1-38d416c47333_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LienCategoryDomain_01a01027-9449-75c9-9653-df92fda66b26" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LienCategoryDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LienCategoryAxis_01a01027-9449-7d75-a4a1-38d416c47333" xlink:to="loc_us-gaap_LienCategoryDomain_01a01027-9449-75c9-9653-df92fda66b26" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorLienMember_01a01027-9449-7383-9267-3773404cc64b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorLienMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LienCategoryDomain_01a01027-9449-75c9-9653-df92fda66b26" xlink:to="loc_us-gaap_SeniorLienMember_01a01027-9449-7383-9267-3773404cc64b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_JuniorLienMember_01a01027-9449-7501-8d37-b217753a7d67" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_JuniorLienMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LienCategoryDomain_01a01027-9449-75c9-9653-df92fda66b26" xlink:to="loc_us-gaap_JuniorLienMember_01a01027-9449-7501-8d37-b217753a7d67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a01027-9449-754a-b99e-d54cad65cb4a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a01027-9449-796e-941a-819f27081f71" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a01027-9449-754a-b99e-d54cad65cb4a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a01027-9449-754a-b99e-d54cad65cb4a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a01027-9449-754a-b99e-d54cad65cb4a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a01027-9449-754a-b99e-d54cad65cb4a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a01027-9449-77ab-8138-06a46a5d213c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a01027-9449-754a-b99e-d54cad65cb4a" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a01027-9449-77ab-8138-06a46a5d213c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_01a01027-9449-7979-8f38-57034bde9613" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a01027-9449-77ab-8138-06a46a5d213c" xlink:to="loc_us-gaap_SeniorNotesMember_01a01027-9449-7979-8f38-57034bde9613" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_01a01027-9449-7840-b53e-c854cee1f99a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a01027-9449-796e-941a-819f27081f71" xlink:to="loc_us-gaap_CreditFacilityAxis_01a01027-9449-7840-b53e-c854cee1f99a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_01a01027-9449-7840-b53e-c854cee1f99a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_01a01027-9449-7840-b53e-c854cee1f99a" xlink:to="loc_us-gaap_CreditFacilityDomain_01a01027-9449-7840-b53e-c854cee1f99a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_01a01027-9449-72d0-95c4-419ddd6cc52b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_01a01027-9449-7840-b53e-c854cee1f99a" xlink:to="loc_us-gaap_CreditFacilityDomain_01a01027-9449-72d0-95c4-419ddd6cc52b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_01a01027-9449-755a-8f07-bab325d43bb4" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_01a01027-9449-72d0-95c4-419ddd6cc52b" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_01a01027-9449-755a-8f07-bab325d43bb4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_DebtInstrumentIncreaseDecreaseInBorrowingCapacity_01a01027-9449-771c-a96e-0eefc823fe9e" xlink:href="bios-20260930.xsd#bios_DebtInstrumentIncreaseDecreaseInBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-742f-b861-a119bbfbe559" xlink:to="loc_bios_DebtInstrumentIncreaseDecreaseInBorrowingCapacity_01a01027-9449-771c-a96e-0eefc823fe9e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_01a01027-9449-78b3-84c4-d465ad3e84be" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-742f-b861-a119bbfbe559" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_01a01027-9449-78b3-84c4-d465ad3e84be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_01a01027-9449-77ad-9941-6d5ca4db3454" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentInterestRateEffectivePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-742f-b861-a119bbfbe559" xlink:to="loc_us-gaap_DebtInstrumentInterestRateEffectivePercentage_01a01027-9449-77ad-9941-6d5ca4db3454" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtWeightedAverageInterestRateOverTime_01a01027-9449-7bf8-ae30-04109abbd71c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtWeightedAverageInterestRateOverTime"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-742f-b861-a119bbfbe559" xlink:to="loc_us-gaap_LongTermDebtWeightedAverageInterestRateOverTime_01a01027-9449-7bf8-ae30-04109abbd71c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_01a01027-9449-7efb-b95c-197d61069816" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LettersOfCreditOutstandingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-742f-b861-a119bbfbe559" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_01a01027-9449-7efb-b95c-197d61069816" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_01a01027-9449-7562-87d7-d8f86e51e613" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-9449-742f-b861-a119bbfbe559" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_01a01027-9449-7562-87d7-d8f86e51e613" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/INDEBTEDNESSScheduleofEstimatedFairValuesofDebtObligationsDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#INDEBTEDNESSScheduleofEstimatedFairValuesofDebtObligationsDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/INDEBTEDNESSScheduleofEstimatedFairValuesofDebtObligationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_01a01027-94f9-76a8-af0e-73c6cef20c1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_01a01027-94f9-79e9-b6b6-b9071e0bce43" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-94f9-76a8-af0e-73c6cef20c1b" xlink:to="loc_us-gaap_DebtInstrumentTable_01a01027-94f9-79e9-b6b6-b9071e0bce43" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a01027-94f9-7788-9c9e-1e94d8800b99" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a01027-94f9-79e9-b6b6-b9071e0bce43" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a01027-94f9-7788-9c9e-1e94d8800b99" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a01027-94f9-7788-9c9e-1e94d8800b99_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a01027-94f9-7788-9c9e-1e94d8800b99" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a01027-94f9-7788-9c9e-1e94d8800b99_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a01027-94f9-7be5-b466-b1ff8dd17eb5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a01027-94f9-7788-9c9e-1e94d8800b99" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a01027-94f9-7be5-b466-b1ff8dd17eb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_01a01027-94f9-7168-bb89-5c7313b7e99b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a01027-94f9-7be5-b466-b1ff8dd17eb5" xlink:to="loc_us-gaap_SeniorNotesMember_01a01027-94f9-7168-bb89-5c7313b7e99b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a01027-94f9-7389-890d-90ecad9a5e5d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a01027-94f9-79e9-b6b6-b9071e0bce43" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a01027-94f9-7389-890d-90ecad9a5e5d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a01027-94f9-7389-890d-90ecad9a5e5d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a01027-94f9-7389-890d-90ecad9a5e5d" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a01027-94f9-7389-890d-90ecad9a5e5d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a01027-94f9-744d-a947-c58965c98235" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_01a01027-94f9-7389-890d-90ecad9a5e5d" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a01027-94f9-744d-a947-c58965c98235" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_01a01027-94f9-7f34-b626-9864caa4d521" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a01027-94f9-744d-a947-c58965c98235" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_01a01027-94f9-7f34-b626-9864caa4d521" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_01a01027-94f9-774c-9d84-56194bc2d949" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a01027-94f9-744d-a947-c58965c98235" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_01a01027-94f9-774c-9d84-56194bc2d949" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_01a01027-94f9-77fa-a04c-d29ea91ebab5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FairValueInputsLevel3Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_01a01027-94f9-744d-a947-c58965c98235" xlink:to="loc_us-gaap_FairValueInputsLevel3Member_01a01027-94f9-77fa-a04c-d29ea91ebab5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a01027-94f9-7e76-9066-8c423c1a4dcc" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_01a01027-94f9-79e9-b6b6-b9071e0bce43" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a01027-94f9-7e76-9066-8c423c1a4dcc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a01027-94f9-7e76-9066-8c423c1a4dcc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a01027-94f9-7e76-9066-8c423c1a4dcc" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a01027-94f9-7e76-9066-8c423c1a4dcc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a01027-94f9-7bb1-aa13-67b531d450ee" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a01027-94f9-7e76-9066-8c423c1a4dcc" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a01027-94f9-7bb1-aa13-67b531d450ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_FirstLienTermLoanMember_01a01027-94f9-7e20-b415-12fa90ae64bb" xlink:href="bios-20260930.xsd#bios_FirstLienTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a01027-94f9-7bb1-aa13-67b531d450ee" xlink:to="loc_bios_FirstLienTermLoanMember_01a01027-94f9-7e20-b415-12fa90ae64bb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebtFairValue_01a01027-94f9-76a2-8582-0e03481240db" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongTermDebtFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_01a01027-94f9-76a8-af0e-73c6cef20c1b" xlink:to="loc_us-gaap_LongTermDebtFairValue_01a01027-94f9-76a2-8582-0e03481240db" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/DERIVATIVEINSTRUMENTSAdditionalInformationDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#DERIVATIVEINSTRUMENTSAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/DERIVATIVEINSTRUMENTSAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_01a01027-94fa-7c65-9ddb-f331aa486968" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_01a01027-94f9-77a5-894d-189495035277" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_01a01027-94fa-7c65-9ddb-f331aa486968" xlink:to="loc_us-gaap_DerivativeTable_01a01027-94f9-77a5-894d-189495035277" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_01a01027-94f9-7336-b9d5-d9ab3d1ba851" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a01027-94f9-77a5-894d-189495035277" xlink:to="loc_us-gaap_DebtInstrumentAxis_01a01027-94f9-7336-b9d5-d9ab3d1ba851" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a01027-94f9-7336-b9d5-d9ab3d1ba851_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a01027-94f9-7336-b9d5-d9ab3d1ba851" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a01027-94f9-7336-b9d5-d9ab3d1ba851_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_01a01027-94f9-7afd-8632-13bdd0fe6279" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_01a01027-94f9-7336-b9d5-d9ab3d1ba851" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_01a01027-94f9-7afd-8632-13bdd0fe6279" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_FirstLienTermLoanMember_01a01027-94f9-7fb6-a5e0-6abe41c1c458" xlink:href="bios-20260930.xsd#bios_FirstLienTermLoanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_01a01027-94f9-7afd-8632-13bdd0fe6279" xlink:to="loc_bios_FirstLienTermLoanMember_01a01027-94f9-7fb6-a5e0-6abe41c1c458" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94f9-7141-b105-d2db0545d7a0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a01027-94f9-77a5-894d-189495035277" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94f9-7141-b105-d2db0545d7a0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94f9-7141-b105-d2db0545d7a0_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94f9-7141-b105-d2db0545d7a0" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94f9-7141-b105-d2db0545d7a0_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94f9-7e35-b0cb-7de69538a8ef" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94f9-7141-b105-d2db0545d7a0" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94f9-7e35-b0cb-7de69538a8ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCapMember_01a01027-94f9-7199-b8c6-6980ca430038" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateCapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94f9-7e35-b0cb-7de69538a8ef" xlink:to="loc_us-gaap_InterestRateCapMember_01a01027-94f9-7199-b8c6-6980ca430038" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_01a01027-94f9-727a-8649-e19ec42d18cf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a01027-94f9-77a5-894d-189495035277" xlink:to="loc_us-gaap_HedgingDesignationAxis_01a01027-94f9-727a-8649-e19ec42d18cf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_01a01027-94f9-727a-8649-e19ec42d18cf_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_01a01027-94f9-727a-8649-e19ec42d18cf" xlink:to="loc_us-gaap_HedgingDesignationDomain_01a01027-94f9-727a-8649-e19ec42d18cf_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_01a01027-94f9-7da2-8183-61b1f71b86ea" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_01a01027-94f9-727a-8649-e19ec42d18cf" xlink:to="loc_us-gaap_HedgingDesignationDomain_01a01027-94f9-7da2-8183-61b1f71b86ea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_01a01027-94f9-78e9-8bcb-bdeafcb2a277" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_01a01027-94f9-7da2-8183-61b1f71b86ea" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_01a01027-94f9-78e9-8bcb-bdeafcb2a277" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_01a01027-94f9-7fd8-80ad-2b4fa613ee19" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a01027-94f9-77a5-894d-189495035277" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_01a01027-94f9-7fd8-80ad-2b4fa613ee19" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a01027-94f9-7fd8-80ad-2b4fa613ee19_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a01027-94f9-7fd8-80ad-2b4fa613ee19" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a01027-94f9-7fd8-80ad-2b4fa613ee19_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_01a01027-94f9-7eb1-9637-15b99e3b727a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_01a01027-94f9-7fd8-80ad-2b4fa613ee19" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_01a01027-94f9-7eb1-9637-15b99e3b727a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SeniorNotesMember_01a01027-94fa-7be1-9690-7d95d2233be2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeniorNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_01a01027-94f9-7eb1-9637-15b99e3b727a" xlink:to="loc_us-gaap_SeniorNotesMember_01a01027-94fa-7be1-9690-7d95d2233be2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeNotionalAmount_01a01027-94fa-70cc-966b-ccc74eada47b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeNotionalAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a01027-94fa-7c65-9ddb-f331aa486968" xlink:to="loc_us-gaap_DerivativeNotionalAmount_01a01027-94fa-70cc-966b-ccc74eada47b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTermOfContract_01a01027-94fa-7add-a0a8-60e2ad178958" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTermOfContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a01027-94fa-7c65-9ddb-f331aa486968" xlink:to="loc_us-gaap_DerivativeTermOfContract_01a01027-94fa-7add-a0a8-60e2ad178958" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/DERIVATIVEINSTRUMENTSScheduleofAmountandLocationofDerivativesintheBalanceSheetDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#DERIVATIVEINSTRUMENTSScheduleofAmountandLocationofDerivativesintheBalanceSheetDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/DERIVATIVEINSTRUMENTSScheduleofAmountandLocationofDerivativesintheBalanceSheetDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_01a01027-94fa-71af-8417-997893a52fb7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_01a01027-94fa-79a4-a368-d53066fc4a87" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_01a01027-94fa-71af-8417-997893a52fb7" xlink:to="loc_us-gaap_DerivativeTable_01a01027-94fa-79a4-a368-d53066fc4a87" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationAxis_01a01027-94fa-7761-9601-b9fae8bb9b2a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a01027-94fa-79a4-a368-d53066fc4a87" xlink:to="loc_us-gaap_HedgingDesignationAxis_01a01027-94fa-7761-9601-b9fae8bb9b2a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_01a01027-94fa-7761-9601-b9fae8bb9b2a_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HedgingDesignationAxis_01a01027-94fa-7761-9601-b9fae8bb9b2a" xlink:to="loc_us-gaap_HedgingDesignationDomain_01a01027-94fa-7761-9601-b9fae8bb9b2a_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HedgingDesignationDomain_01a01027-94fa-70e4-8b41-43b8e08044dd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_HedgingDesignationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HedgingDesignationAxis_01a01027-94fa-7761-9601-b9fae8bb9b2a" xlink:to="loc_us-gaap_HedgingDesignationDomain_01a01027-94fa-70e4-8b41-43b8e08044dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DesignatedAsHedgingInstrumentMember_01a01027-94fa-7729-9b71-16510e023af7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DesignatedAsHedgingInstrumentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HedgingDesignationDomain_01a01027-94fa-70e4-8b41-43b8e08044dd" xlink:to="loc_us-gaap_DesignatedAsHedgingInstrumentMember_01a01027-94fa-7729-9b71-16510e023af7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94fa-7617-a043-702166b7398d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a01027-94fa-79a4-a368-d53066fc4a87" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94fa-7617-a043-702166b7398d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94fa-7617-a043-702166b7398d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94fa-7617-a043-702166b7398d" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94fa-7617-a043-702166b7398d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94fa-71d5-847a-6685994b8d15" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94fa-7617-a043-702166b7398d" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94fa-71d5-847a-6685994b8d15" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCapMember_01a01027-94fa-798b-8159-df538ee596a9" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateCapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94fa-71d5-847a-6685994b8d15" xlink:to="loc_us-gaap_InterestRateCapMember_01a01027-94fa-798b-8159-df538ee596a9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssets_01a01027-94fa-7bdd-a8c5-2b696659e39a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a01027-94fa-71af-8417-997893a52fb7" xlink:to="loc_us-gaap_DerivativeAssets_01a01027-94fa-7bdd-a8c5-2b696659e39a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration_01a01027-94fa-72aa-961a-ac2a6abba2f8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a01027-94fa-71af-8417-997893a52fb7" xlink:to="loc_us-gaap_DerivativeAssetStatementOfFinancialPositionExtensibleEnumeration_01a01027-94fa-72aa-961a-ac2a6abba2f8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/DERIVATIVEINSTRUMENTSScheduleofPreTaxGainLossonDerivativeInstrumentsDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#DERIVATIVEINSTRUMENTSScheduleofPreTaxGainLossonDerivativeInstrumentsDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/DERIVATIVEINSTRUMENTSScheduleofPreTaxGainLossonDerivativeInstrumentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeLineItems_01a01027-94fa-7833-8e41-74c8afa7adf1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeTable_01a01027-94fa-7d50-a2e2-a24637438476" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DerivativeLineItems_01a01027-94fa-7833-8e41-74c8afa7adf1" xlink:to="loc_us-gaap_DerivativeTable_01a01027-94fa-7d50-a2e2-a24637438476" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94fa-7daa-873f-eab6598dae93" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeInstrumentRiskAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DerivativeTable_01a01027-94fa-7d50-a2e2-a24637438476" xlink:to="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94fa-7daa-873f-eab6598dae93" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94fa-7daa-873f-eab6598dae93_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94fa-7daa-873f-eab6598dae93" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94fa-7daa-873f-eab6598dae93_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94fa-7a11-81ed-0648913bd924" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DerivativeContractTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DerivativeInstrumentRiskAxis_01a01027-94fa-7daa-873f-eab6598dae93" xlink:to="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94fa-7a11-81ed-0648913bd924" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestRateCapMember_01a01027-94fa-78d0-ba35-649498950065" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestRateCapMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeContractTypeDomain_01a01027-94fa-7a11-81ed-0648913bd924" xlink:to="loc_us-gaap_InterestRateCapMember_01a01027-94fa-78d0-ba35-649498950065" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_01a01027-94fa-7ea6-ae96-2d211e2f7a35" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a01027-94fa-7833-8e41-74c8afa7adf1" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax_01a01027-94fa-7ea6-ae96-2d211e2f7a35" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_01a01027-94fa-7a7d-b1b9-c676a4d50790" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DerivativeLineItems_01a01027-94fa-7833-8e41-74c8afa7adf1" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossCashFlowHedgeGainLossReclassificationBeforeTax_01a01027-94fa-7a7d-b1b9-c676a4d50790" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/STOCKBASEDINCENTIVECOMPENSATIONDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#STOCKBASEDINCENTIVECOMPENSATIONDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/STOCKBASEDINCENTIVECOMPENSATIONDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a01027-94fa-7eed-9052-ac2fe7462b7b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_01a01027-94fa-76fe-8648-4895b01c74bb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a01027-94fa-7eed-9052-ac2fe7462b7b" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_01a01027-94fa-76fe-8648-4895b01c74bb" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_01a01027-94fa-7f74-bee9-c1d5a485d6d8" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_01a01027-94fa-76fe-8648-4895b01c74bb" xlink:to="loc_us-gaap_PlanNameAxis_01a01027-94fa-7f74-bee9-c1d5a485d6d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_01a01027-94fa-7f74-bee9-c1d5a485d6d8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_01a01027-94fa-7f74-bee9-c1d5a485d6d8" xlink:to="loc_us-gaap_PlanNameDomain_01a01027-94fa-7f74-bee9-c1d5a485d6d8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_01a01027-94fa-7c31-948b-ac2fc1fdf0e2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_01a01027-94fa-7f74-bee9-c1d5a485d6d8" xlink:to="loc_us-gaap_PlanNameDomain_01a01027-94fa-7c31-948b-ac2fc1fdf0e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_A2018PlanMember_01a01027-94fa-73cb-80cf-f120c757ee81" xlink:href="bios-20260930.xsd#bios_A2018PlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_01a01027-94fa-7c31-948b-ac2fc1fdf0e2" xlink:to="loc_bios_A2018PlanMember_01a01027-94fa-73cb-80cf-f120c757ee81" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_01a01027-94fa-7597-b551-51197e9ab944" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_01a01027-94fa-76fe-8648-4895b01c74bb" xlink:to="loc_us-gaap_AwardTypeAxis_01a01027-94fa-7597-b551-51197e9ab944" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a01027-94fa-7597-b551-51197e9ab944_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_01a01027-94fa-7597-b551-51197e9ab944" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a01027-94fa-7597-b551-51197e9ab944_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a01027-94fa-7945-82a8-d505bea7ab0d" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_01a01027-94fa-7597-b551-51197e9ab944" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a01027-94fa-7945-82a8-d505bea7ab0d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_HCIIncentiveUnitsMember_01a01027-94fa-7a15-bc09-ad588fe56a59" xlink:href="bios-20260930.xsd#bios_HCIIncentiveUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_01a01027-94fa-7945-82a8-d505bea7ab0d" xlink:to="loc_bios_HCIIncentiveUnitsMember_01a01027-94fa-7a15-bc09-ad588fe56a59" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_01a01027-94fa-7b8b-9db7-edfc6daa01b1" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a01027-94fa-7eed-9052-ac2fe7462b7b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_01a01027-94fa-7b8b-9db7-edfc6daa01b1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_01a01027-94fa-75e5-96ca-b99287f8f837" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a01027-94fa-7eed-9052-ac2fe7462b7b" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized_01a01027-94fa-75e5-96ca-b99287f8f837" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_01a01027-94fa-76d1-9de0-936c638a00d2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AllocatedShareBasedCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_01a01027-94fa-7eed-9052-ac2fe7462b7b" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_01a01027-94fa-76d1-9de0-936c638a00d2" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/STOCKHOLDERSEQUITYAdditionalInformationDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#STOCKHOLDERSEQUITYAdditionalInformationDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/STOCKHOLDERSEQUITYAdditionalInformationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a01027-94fa-7acb-913b-0acb624af43f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightTable_01a01027-94fa-7e74-a5f2-2057dfdb38c7" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a01027-94fa-7acb-913b-0acb624af43f" xlink:to="loc_us-gaap_ClassOfWarrantOrRightTable_01a01027-94fa-7e74-a5f2-2057dfdb38c7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramAxis_01a01027-94fa-7eb3-96b3-53342abead05" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ShareRepurchaseProgramAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ClassOfWarrantOrRightTable_01a01027-94fa-7e74-a5f2-2057dfdb38c7" xlink:to="loc_srt_ShareRepurchaseProgramAxis_01a01027-94fa-7eb3-96b3-53342abead05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramDomain_01a01027-94fa-7eb3-96b3-53342abead05_default" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ShareRepurchaseProgramAxis_01a01027-94fa-7eb3-96b3-53342abead05" xlink:to="loc_srt_ShareRepurchaseProgramDomain_01a01027-94fa-7eb3-96b3-53342abead05_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ShareRepurchaseProgramDomain_01a01027-94fa-7fc4-8af3-79928c6e11cf" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ShareRepurchaseProgramDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ShareRepurchaseProgramAxis_01a01027-94fa-7eb3-96b3-53342abead05" xlink:to="loc_srt_ShareRepurchaseProgramDomain_01a01027-94fa-7fc4-8af3-79928c6e11cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_CommonStockRepurchaseProgramMember_01a01027-94fa-7ac1-82b3-0c13a2c23bb0" xlink:href="bios-20260930.xsd#bios_CommonStockRepurchaseProgramMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ShareRepurchaseProgramDomain_01a01027-94fa-7fc4-8af3-79928c6e11cf" xlink:to="loc_bios_CommonStockRepurchaseProgramMember_01a01027-94fa-7ac1-82b3-0c13a2c23bb0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_01a01027-94fa-7a7b-962d-04db839cdb33" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a01027-94fa-7acb-913b-0acb624af43f" xlink:to="loc_us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights_01a01027-94fa-7a7b-962d-04db839cdb33" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_01a01027-94fa-7a12-b9d2-80e70efc4e69" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a01027-94fa-7acb-913b-0acb624af43f" xlink:to="loc_srt_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased_01a01027-94fa-7a12-b9d2-80e70efc4e69" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockSharesAcquired_01a01027-94fa-7884-9fa9-2d064ff1e086" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockSharesAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a01027-94fa-7acb-913b-0acb624af43f" xlink:to="loc_us-gaap_TreasuryStockSharesAcquired_01a01027-94fa-7884-9fa9-2d064ff1e086" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockAcquiredAverageCostPerShare_01a01027-94fa-7416-a295-b66d1f5fe951" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockAcquiredAverageCostPerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a01027-94fa-7acb-913b-0acb624af43f" xlink:to="loc_us-gaap_TreasuryStockAcquiredAverageCostPerShare_01a01027-94fa-7416-a295-b66d1f5fe951" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_01a01027-94fa-7628-ab90-56b7b6bd827e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_TreasuryStockValueAcquiredCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a01027-94fa-7acb-913b-0acb624af43f" xlink:to="loc_us-gaap_TreasuryStockValueAcquiredCostMethod_01a01027-94fa-7628-ab90-56b7b6bd827e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StockRepurchaseProgramAuthorizedAmount1_01a01027-94fa-7635-a6e9-045bc00bee35" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StockRepurchaseProgramAuthorizedAmount1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfWarrantOrRightLineItems_01a01027-94fa-7acb-913b-0acb624af43f" xlink:to="loc_srt_StockRepurchaseProgramAuthorizedAmount1_01a01027-94fa-7635-a6e9-045bc00bee35" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/STOCKHOLDERSEQUITYScheduleofChangesinSharesofCommonStockDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#STOCKHOLDERSEQUITYScheduleofChangesinSharesofCommonStockDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/STOCKHOLDERSEQUITYScheduleofChangesinSharesofCommonStockDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClassOfStockLineItems_01a01027-94fa-7282-bc41-7b81e881b268" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfStockByClassTable_01a01027-94fa-7d63-9695-9eb3b6a122ed" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a01027-94fa-7282-bc41-7b81e881b268" xlink:to="loc_us-gaap_ScheduleOfStockByClassTable_01a01027-94fa-7d63-9695-9eb3b6a122ed" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_01a01027-94fa-7b47-b6b8-6c7cfd1b6ccd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfStockByClassTable_01a01027-94fa-7d63-9695-9eb3b6a122ed" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_01a01027-94fa-7b47-b6b8-6c7cfd1b6ccd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a01027-94fa-7b47-b6b8-6c7cfd1b6ccd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a01027-94fa-7b47-b6b8-6c7cfd1b6ccd" xlink:to="loc_us-gaap_EquityComponentDomain_01a01027-94fa-7b47-b6b8-6c7cfd1b6ccd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_01a01027-94fa-7145-b598-0574ae206c98" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_01a01027-94fa-7b47-b6b8-6c7cfd1b6ccd" xlink:to="loc_us-gaap_EquityComponentDomain_01a01027-94fa-7145-b598-0574ae206c98" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_01a01027-94fa-778d-9431-d2033bccea25" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_01a01027-94fa-7145-b598-0574ae206c98" xlink:to="loc_us-gaap_CommonStockMember_01a01027-94fa-778d-9431-d2033bccea25" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-94fa-7b5f-b5c3-83faab7cd00a" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ClassOfStockLineItems_01a01027-94fa-7282-bc41-7b81e881b268" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-94fa-7b5f-b5c3-83faab7cd00a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_01a01027-94fa-7c77-be21-87d21ceb1c93" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-94fa-7b5f-b5c3-83faab7cd00a" xlink:to="loc_us-gaap_CommonStockSharesOutstanding_01a01027-94fa-7c77-be21-87d21ceb1c93" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_01a01027-94fa-701d-8e68-8ed2a2c4c255" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesNewIssues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-94fa-7b5f-b5c3-83faab7cd00a" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesNewIssues_01a01027-94fa-701d-8e68-8ed2a2c4c255" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_01a01027-94fa-73cb-9a49-c1bb991b7b1b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_01a01027-94fa-7b5f-b5c3-83faab7cd00a" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_01a01027-94fa-73cb-9a49-c1bb991b7b1b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesOutstanding_01a01027-94fa-79a6-8e85-09ea8f17ec35" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/RELATEDPARTYTRANSACTIONSDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#RELATEDPARTYTRANSACTIONSDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/RELATEDPARTYTRANSACTIONSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionLineItems_01a01027-94fa-7b40-be8f-8cef19e42dbb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a01027-94fa-781d-82e6-8eacefba6dc5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a01027-94fa-7b40-be8f-8cef19e42dbb" xlink:to="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a01027-94fa-781d-82e6-8eacefba6dc5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a01027-94fa-777e-992b-f31ca927b68f" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable_01a01027-94fa-781d-82e6-8eacefba6dc5" xlink:to="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a01027-94fa-777e-992b-f31ca927b68f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a01027-94fa-777e-992b-f31ca927b68f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a01027-94fa-777e-992b-f31ca927b68f" xlink:to="loc_us-gaap_RelatedPartyDomain_01a01027-94fa-777e-992b-f31ca927b68f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyDomain_01a01027-94fa-7d7d-8f11-aaedcf82a567" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_01a01027-94fa-777e-992b-f31ca927b68f" xlink:to="loc_us-gaap_RelatedPartyDomain_01a01027-94fa-7d7d-8f11-aaedcf82a567" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateJointVentureMember_01a01027-94fa-7fd4-ad88-dd107aa59504" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CorporateJointVentureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyDomain_01a01027-94fa-7d7d-8f11-aaedcf82a567" xlink:to="loc_us-gaap_CorporateJointVentureMember_01a01027-94fa-7fd4-ad88-dd107aa59504" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a01027-94fa-7f72-8c8e-e12209cd0e21" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a01027-94fa-7b40-be8f-8cef19e42dbb" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a01027-94fa-7f72-8c8e-e12209cd0e21" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_01a01027-94fa-78d9-a49d-f5b48a9fa9f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentDividendsOrDistributions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a01027-94fa-7b40-be8f-8cef19e42dbb" xlink:to="loc_us-gaap_EquityMethodInvestmentDividendsOrDistributions_01a01027-94fa-78d9-a49d-f5b48a9fa9f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsPayableOtherCurrentAndNoncurrent_01a01027-94fa-7c83-8c02-19c3690e4a53" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableOtherCurrentAndNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RelatedPartyTransactionLineItems_01a01027-94fa-7b40-be8f-8cef19e42dbb" xlink:to="loc_us-gaap_AccountsPayableOtherCurrentAndNoncurrent_01a01027-94fa-7c83-8c02-19c3690e4a53" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/SEGMENTREPORTINGDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#SEGMENTREPORTINGDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/SEGMENTREPORTINGDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_01a01027-94fa-7cbf-af19-a12c1c7c2621" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentReportingInformationLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a01027-94fa-7468-8ef1-7135f6977493" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a01027-94fa-7cbf-af19-a12c1c7c2621" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a01027-94fa-7468-8ef1-7135f6977493" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_01a01027-94fa-77c6-ab68-eefab097fe66" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_01a01027-94fa-7468-8ef1-7135f6977493" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_01a01027-94fa-77c6-ab68-eefab097fe66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01a01027-94fa-77c6-ab68-eefab097fe66_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01a01027-94fa-77c6-ab68-eefab097fe66" xlink:to="loc_us-gaap_SegmentDomain_01a01027-94fa-77c6-ab68-eefab097fe66_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01a01027-94fa-7f55-8a76-d1e6ce01861c" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01a01027-94fa-77c6-ab68-eefab097fe66" xlink:to="loc_us-gaap_SegmentDomain_01a01027-94fa-7f55-8a76-d1e6ce01861c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_ReportableSegmentMember_01a01027-94fa-76df-9042-88c3f3e84b31" xlink:href="bios-20260930.xsd#bios_ReportableSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_01a01027-94fa-7f55-8a76-d1e6ce01861c" xlink:to="loc_bios_ReportableSegmentMember_01a01027-94fa-76df-9042-88c3f3e84b31" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a01027-94fa-7b98-af25-c42de420c08b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a01027-94fa-7cbf-af19-a12c1c7c2621" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax_01a01027-94fa-7b98-af25-c42de420c08b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIncome_01a01027-94fa-7140-b73f-8b7e9a40e4f2" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherIncome"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a01027-94fa-7cbf-af19-a12c1c7c2621" xlink:to="loc_us-gaap_OtherIncome_01a01027-94fa-7140-b73f-8b7e9a40e4f2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_01a01027-94fa-7553-8574-2eac80819054" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a01027-94fa-7cbf-af19-a12c1c7c2621" xlink:to="loc_us-gaap_Revenues_01a01027-94fa-7553-8574-2eac80819054" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_IncomeExpenseAbstract_01a01027-94fa-7755-9e3b-988dc5ac16f4" xlink:href="bios-20260930.xsd#bios_IncomeExpenseAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a01027-94fa-7cbf-af19-a12c1c7c2621" xlink:to="loc_bios_IncomeExpenseAbstract_01a01027-94fa-7755-9e3b-988dc5ac16f4" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfRevenue_01a01027-94fa-74e6-8f7c-ecb1bd9d33eb" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CostOfRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bios_IncomeExpenseAbstract_01a01027-94fa-7755-9e3b-988dc5ac16f4" xlink:to="loc_us-gaap_CostOfRevenue_01a01027-94fa-74e6-8f7c-ecb1bd9d33eb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LaborAndRelatedExpense_01a01027-94fa-731a-835d-75cbce7e7bc5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LaborAndRelatedExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bios_IncomeExpenseAbstract_01a01027-94fa-7755-9e3b-988dc5ac16f4" xlink:to="loc_us-gaap_LaborAndRelatedExpense_01a01027-94fa-731a-835d-75cbce7e7bc5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating_01a01027-94fa-722c-a1e5-90c7fb4081c5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherCostAndExpenseOperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bios_IncomeExpenseAbstract_01a01027-94fa-7755-9e3b-988dc5ac16f4" xlink:to="loc_us-gaap_OtherCostAndExpenseOperating_01a01027-94fa-722c-a1e5-90c7fb4081c5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_01a01027-94fa-79a5-8a61-ea1e34b93246" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bios_IncomeExpenseAbstract_01a01027-94fa-7755-9e3b-988dc5ac16f4" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_01a01027-94fa-79a5-8a61-ea1e34b93246" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InterestExpenseNonoperating_01a01027-94fa-7378-a845-0808915ae2fd" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_InterestExpenseNonoperating"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bios_IncomeExpenseAbstract_01a01027-94fa-7755-9e3b-988dc5ac16f4" xlink:to="loc_us-gaap_InterestExpenseNonoperating_01a01027-94fa-7378-a845-0808915ae2fd" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_01a01027-94fa-7752-b2e5-12a6286784ac" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromEquityMethodInvestments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bios_IncomeExpenseAbstract_01a01027-94fa-7755-9e3b-988dc5ac16f4" xlink:to="loc_us-gaap_IncomeLossFromEquityMethodInvestments_01a01027-94fa-7752-b2e5-12a6286784ac" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherNonoperatingIncomeExpense_01a01027-94fa-759b-ab34-ee1142a0789b" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherNonoperatingIncomeExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bios_IncomeExpenseAbstract_01a01027-94fa-7755-9e3b-988dc5ac16f4" xlink:to="loc_us-gaap_OtherNonoperatingIncomeExpense_01a01027-94fa-759b-ab34-ee1142a0789b" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_01a01027-94fa-7765-a75a-d7e3b7b3ec11" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_bios_IncomeExpenseAbstract_01a01027-94fa-7755-9e3b-988dc5ac16f4" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_01a01027-94fa-7765-a75a-d7e3b7b3ec11" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_01a01027-94fa-7e4d-8da7-296af03d4f0e" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_01a01027-94fa-7cbf-af19-a12c1c7c2621" xlink:to="loc_us-gaap_NetIncomeLoss_01a01027-94fa-7e4d-8da7-296af03d4f0e" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.bioscrip.com/role/SUBSEQUENTEVENTSDetails" xlink:type="simple" xlink:href="bios-20260930.xsd#SUBSEQUENTEVENTSDetails"/>
  <link:definitionLink xlink:role="http://www.bioscrip.com/role/SUBSEQUENTEVENTSDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventLineItems_01a01027-94fa-74a3-b9fc-8162e3c2f894" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTable_01a01027-94fa-792a-86d6-3794bc94fcb0" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SubsequentEventLineItems_01a01027-94fa-74a3-b9fc-8162e3c2f894" xlink:to="loc_us-gaap_SubsequentEventTable_01a01027-94fa-792a-86d6-3794bc94fcb0" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_01a01027-94fa-79e5-b94c-73e0cdaccd32" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_01a01027-94fa-792a-86d6-3794bc94fcb0" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_01a01027-94fa-79e5-b94c-73e0cdaccd32" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a01027-94fa-79e5-b94c-73e0cdaccd32_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a01027-94fa-79e5-b94c-73e0cdaccd32" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a01027-94fa-79e5-b94c-73e0cdaccd32_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_01a01027-94fa-7069-ab40-b717c71f5911" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_01a01027-94fa-79e5-b94c-73e0cdaccd32" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_01a01027-94fa-7069-ab40-b717c71f5911" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SubsequentEventMember_01a01027-94fa-7ead-986d-9d818a864caf" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventTypeDomain_01a01027-94fa-7069-ab40-b717c71f5911" xlink:to="loc_us-gaap_SubsequentEventMember_01a01027-94fa-7ead-986d-9d818a864caf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_01a01027-94fa-75c0-acd3-510982cc8824" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SubsequentEventTable_01a01027-94fa-792a-86d6-3794bc94fcb0" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_01a01027-94fa-75c0-acd3-510982cc8824" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-94fa-75c0-acd3-510982cc8824_default" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01a01027-94fa-75c0-acd3-510982cc8824" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-94fa-75c0-acd3-510982cc8824_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-94fa-7c57-a498-e2aae3e22310" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_01a01027-94fa-75c0-acd3-510982cc8824" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-94fa-7c57-a498-e2aae3e22310" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_bios_OnyxBidcoOnyxMergerSubMember_01a1413d-42f9-7334-8f47-3aa3564b681b" xlink:href="bios-20260930.xsd#bios_OnyxBidcoOnyxMergerSubMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_01a01027-94fa-7c57-a498-e2aae3e22310" xlink:to="loc_bios_OnyxBidcoOnyxMergerSubMember_01a1413d-42f9-7334-8f47-3aa3564b681b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionSharePrice_01a1413b-5849-7fef-b1c5-e4a65b2f38b5" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_BusinessAcquisitionSharePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SubsequentEventLineItems_01a01027-94fa-74a3-b9fc-8162e3c2f894" xlink:to="loc_us-gaap_BusinessAcquisitionSharePrice_01a1413b-5849-7fef-b1c5-e4a65b2f38b5" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/srt/role/srt-eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-roles-2026.xsd#eedm1"/>
  <link:definitionLink xlink:role="http://fasb.org/srt/role/srt-eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PrepaidExpenseAndOtherAssetsCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsAbstract" xlink:to="loc_us-gaap_PrepaidExpenseAndOtherAssetsCurrent" xlink:type="arc" order="101"/>
  </link:definitionLink>
</link:linkbase>
