<?xml version="1.0" encoding="US-ASCII" standalone="no"?>
    <!-- Field: Doc-Info; Name: Generator; Value: GoFiler Complete; Version: 6.5a -->
    <!-- Field: Doc-Info; Name: VendorURI; Value: https://www.novaworks.com -->
    <!-- Field: Doc-Info; Name: Status; Value: 0x00000000 -->
<link:linkbase xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:xbrli="http://www.xbrl.org/2003/instance" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#Cover" roleURI="http://modulinktech.com/role/Cover" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#ConsolidatedBalanceSheets" roleURI="http://modulinktech.com/role/ConsolidatedBalanceSheets" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#ConsolidatedBalanceSheetsParenthetical" roleURI="http://modulinktech.com/role/ConsolidatedBalanceSheetsParenthetical" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#ConsolidatedStatementsOfOperationsAndComprehensiveLoss" roleURI="http://modulinktech.com/role/ConsolidatedStatementsOfOperationsAndComprehensiveLoss" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#ConsolidatedStatementsOfStockholdersEquity" roleURI="http://modulinktech.com/role/ConsolidatedStatementsOfStockholdersEquity" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#ConsolidatedStatementsOfCashFlows" roleURI="http://modulinktech.com/role/ConsolidatedStatementsOfCashFlows" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#OrganizationAndPrincipalActivities" roleURI="http://modulinktech.com/role/OrganizationAndPrincipalActivities" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#SummaryOfSignificantAccountingPolicies" roleURI="http://modulinktech.com/role/SummaryOfSignificantAccountingPolicies" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#Subsidiaries" roleURI="http://modulinktech.com/role/Subsidiaries" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AccountsReceivable" roleURI="http://modulinktech.com/role/AccountsReceivable" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#ContractLiabilities" roleURI="http://modulinktech.com/role/ContractLiabilities" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#PrepaidExpensesAndOtherCurrentAssetsNet" roleURI="http://modulinktech.com/role/PrepaidExpensesAndOtherCurrentAssetsNet" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AmountDueFromRelatedCompany" roleURI="http://modulinktech.com/role/AmountDueFromRelatedCompany" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AmountDueFromAssociate" roleURI="http://modulinktech.com/role/AmountDueFromAssociate" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AmountDueFromImmediateHoldingCompany" roleURI="http://modulinktech.com/role/AmountDueFromImmediateHoldingCompany" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#LoanReceivables" roleURI="http://modulinktech.com/role/LoanReceivables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#EquipmentNet" roleURI="http://modulinktech.com/role/EquipmentNet" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#InvestmentInAssociate" roleURI="http://modulinktech.com/role/InvestmentInAssociate" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#LongTermPrepayment" roleURI="http://modulinktech.com/role/LongTermPrepayment" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AccountsPayable" roleURI="http://modulinktech.com/role/AccountsPayable" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AmountDueToRelatedCompanies" roleURI="http://modulinktech.com/role/AmountDueToRelatedCompanies" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AmountDueToDirectors" roleURI="http://modulinktech.com/role/AmountDueToDirectors" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#NotesPayable" roleURI="http://modulinktech.com/role/NotesPayable" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#CommitmentsAndContingencies" roleURI="http://modulinktech.com/role/CommitmentsAndContingencies" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#StockholdersEquity" roleURI="http://modulinktech.com/role/StockholdersEquity" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#RelatedPartyTransactions" roleURI="http://modulinktech.com/role/RelatedPartyTransactions" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#NetLossPerOrdinaryShare" roleURI="http://modulinktech.com/role/NetLossPerOrdinaryShare" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#Revenue" roleURI="http://modulinktech.com/role/Revenue" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#IncomeTaxes" roleURI="http://modulinktech.com/role/IncomeTaxes" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#SubsequentEvents" roleURI="http://modulinktech.com/role/SubsequentEvents" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#SummaryOfSignificantAccountingPoliciesPolicies" roleURI="http://modulinktech.com/role/SummaryOfSignificantAccountingPoliciesPolicies" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#SubsidiariesTables" roleURI="http://modulinktech.com/role/SubsidiariesTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AccountsReceivableTables" roleURI="http://modulinktech.com/role/AccountsReceivableTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#ContractLiabilitiesTables" roleURI="http://modulinktech.com/role/ContractLiabilitiesTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#PrepaidExpensesAndOtherCurrentAssetsNetTables" roleURI="http://modulinktech.com/role/PrepaidExpensesAndOtherCurrentAssetsNetTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#EquipmentNetTables" roleURI="http://modulinktech.com/role/EquipmentNetTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#InvestmentInAssociateTables" roleURI="http://modulinktech.com/role/InvestmentInAssociateTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AccountsPayableTables" roleURI="http://modulinktech.com/role/AccountsPayableTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AmountDueToRelatedCompaniesTables" roleURI="http://modulinktech.com/role/AmountDueToRelatedCompaniesTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#NotesPayableTables" roleURI="http://modulinktech.com/role/NotesPayableTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#RelatedPartyTransactionsTables" roleURI="http://modulinktech.com/role/RelatedPartyTransactionsTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#NetLossPerOrdinaryShareTables" roleURI="http://modulinktech.com/role/NetLossPerOrdinaryShareTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#RevenueTables" roleURI="http://modulinktech.com/role/RevenueTables" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#OrganizationAndPrincipalActivitiesDetailsNarrative" roleURI="http://modulinktech.com/role/OrganizationAndPrincipalActivitiesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#SubsidiariesDetails" roleURI="http://modulinktech.com/role/SubsidiariesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AccountsReceivableDetails" roleURI="http://modulinktech.com/role/AccountsReceivableDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AccountsReceivableDetailsNarrative" roleURI="http://modulinktech.com/role/AccountsReceivableDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#ContractAssetsAndLiabilitiesDetails-ContractLiabilities" roleURI="http://modulinktech.com/role/ContractAssetsAndLiabilitiesDetails-ContractLiabilities" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#PrepaidExpensesAndOtherCurrentAssetsNetDetails" roleURI="http://modulinktech.com/role/PrepaidExpensesAndOtherCurrentAssetsNetDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#LoanReceivablesDetailsNarrative" roleURI="http://modulinktech.com/role/LoanReceivablesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#EquipmentNetDetails" roleURI="http://modulinktech.com/role/EquipmentNetDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#EquipmentNetDetailsNarrative" roleURI="http://modulinktech.com/role/EquipmentNetDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#InvestmentInAssociateDetails" roleURI="http://modulinktech.com/role/InvestmentInAssociateDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#InvestmentInAssociateDetails-FinancialInformation" roleURI="http://modulinktech.com/role/InvestmentInAssociateDetails-FinancialInformation" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AccountsPayableDetails" roleURI="http://modulinktech.com/role/AccountsPayableDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AccountsPayableDetailsNarrative" roleURI="http://modulinktech.com/role/AccountsPayableDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#AmountDueToRelatedCompaniesDetails" roleURI="http://modulinktech.com/role/AmountDueToRelatedCompaniesDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#NotesPayableDetails" roleURI="http://modulinktech.com/role/NotesPayableDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#NotesPayableDetailsNarrative" roleURI="http://modulinktech.com/role/NotesPayableDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#CommitmentsAndContingenciesDetailsNarrative" roleURI="http://modulinktech.com/role/CommitmentsAndContingenciesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#StockholdersEquityDetailsNarrative" roleURI="http://modulinktech.com/role/StockholdersEquityDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#RelatedPartyTransactionsDetails" roleURI="http://modulinktech.com/role/RelatedPartyTransactionsDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#RelatedPartyTransactionsDetailsNarrative" roleURI="http://modulinktech.com/role/RelatedPartyTransactionsDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#NetLossPerOrdinaryShareDetails" roleURI="http://modulinktech.com/role/NetLossPerOrdinaryShareDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#RevenueDetails" roleURI="http://modulinktech.com/role/RevenueDetails" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#IncomeTaxesDetailsNarrative" roleURI="http://modulinktech.com/role/IncomeTaxesDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="mdlk-20260331.xsd#SegmentReportingDetailsNarrative" roleURI="http://modulinktech.com/role/SegmentReportingDetailsNarrative" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#PvpExecutiveCategoriesOnly" roleURI="http://xbrl.sec.gov/ecd/role/PvpExecutiveCategoriesOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#PvpAdjustmentsOnly" roleURI="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#IndividualsOnly" roleURI="http://xbrl.sec.gov/ecd/role/IndividualsOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#AwardTypeOnly" roleURI="http://xbrl.sec.gov/ecd/AwardTypeOnly" />
    <link:roleRef xlink:type="simple" xlink:href="https://xbrl.sec.gov/ecd/2026/ecd-2026.xsd#TradingArrangmentsOnly" roleURI="http://xbrl.sec.gov/ecd/role/TradingArrangementsOnly" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension" arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member" arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all" arcroleURI="http://xbrl.org/int/dim/arcrole/all" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll" arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" />
    <link:arcroleRef xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default" arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/Cover" xlink:title="00000001 - Document - Cover" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/ConsolidatedBalanceSheets" xlink:title="00000002 - Statement - CONSOLIDATED BALANCE SHEETS" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/ConsolidatedBalanceSheetsParenthetical" xlink:title="00000003 - Statement - CONSOLIDATED BALANCE SHEETS (Parenthetical)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaapStatementClassOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementClassOfStockAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SeriesAPreferredStockMember" xlink:label="loc_us-gaapSeriesAPreferredStockMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapSeriesAPreferredStockMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaapPreferredStockParOrStatedValuePerShare_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockParOrStatedValuePerShare_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaapPreferredStockSharesAuthorized_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesAuthorized_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaapPreferredStockSharesIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesIssued_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaapPreferredStockSharesOutstanding_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapPreferredStockSharesOutstanding_50" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaapCommonStockParOrStatedValuePerShare_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockParOrStatedValuePerShare_50" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaapCommonStockSharesAuthorized_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesAuthorized_50" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaapCommonStockSharesIssued_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesIssued_50" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaapCommonStockSharesOutstanding_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapCommonStockSharesOutstanding_50" xlink:type="arc" order="7" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/ConsolidatedStatementsOfOperationsAndComprehensiveLoss" xlink:title="00000004 - Statement - CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (UNAUDITED)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/ConsolidatedStatementsOfStockholdersEquity" xlink:title="00000005 - Statement - CONSOLIDATED STATEMENTS OF STOCKHOLDERS&apos; EQUITY (UNAUDITED)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaapStatementLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaapStatementTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStatementTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaapStatementEquityComponentsAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapStatementTable" xlink:to="loc_us-gaapStatementEquityComponentsAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaapEquityComponentDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementEquityComponentsAxis" xlink:to="loc_us-gaapEquityComponentDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaapCommonStockMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapCommonStockMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaapPreferredStockMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapPreferredStockMember_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaapAdditionalPaidInCapitalMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapAdditionalPaidInCapitalMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ExchangeReserveMember" xlink:label="loc_MDLKExchangeReserveMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_MDLKExchangeReserveMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsMember" xlink:label="loc_us-gaapRetainedEarningsMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapEquityComponentDomain" xlink:to="loc_us-gaapRetainedEarningsMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquity" xlink:label="loc_us-gaapStockholdersEquity_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapStockholdersEquity_70" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesOutstanding" xlink:label="loc_us-gaapSharesOutstanding_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapSharesOutstanding_70" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalOther" xlink:label="loc_us-gaapAdjustmentsToAdditionalPaidInCapitalOther_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapAdjustmentsToAdditionalPaidInCapitalOther_70" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapStatementLineItems" xlink:to="loc_us-gaapNetIncomeLoss_70" xlink:type="arc" order="4" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/ConsolidatedStatementsOfCashFlows" xlink:title="00000006 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/OrganizationAndPrincipalActivities" xlink:title="999012 - Disclosure - ORGANIZATION AND PRINCIPAL ACTIVITIES" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/SummaryOfSignificantAccountingPolicies" xlink:title="999013 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/Subsidiaries" xlink:title="999014 - Disclosure - SUBSIDIARIES" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AccountsReceivable" xlink:title="999015 - Disclosure - ACCOUNTS RECEIVABLE" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/ContractLiabilities" xlink:title="999016 - Disclosure - CONTRACT LIABILITIES" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/PrepaidExpensesAndOtherCurrentAssetsNet" xlink:title="999017 - Disclosure - PREPAID EXPENSES AND OTHER CURRENT ASSETS, NET" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AmountDueFromRelatedCompany" xlink:title="999018 - Disclosure - AMOUNT DUE FROM A RELATED COMPANY" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AmountDueFromAssociate" xlink:title="999019 - Disclosure - AMOUNT DUE FROM AN ASSOCIATE" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AmountDueFromImmediateHoldingCompany" xlink:title="999020 - Disclosure - AMOUNT DUE FROM IMMEDIATE HOLDING COMPANY" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/LoanReceivables" xlink:title="999021 - Disclosure - LOAN RECEIVABLES" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/EquipmentNet" xlink:title="999022 - Disclosure - EQUIPMENT, NET" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/InvestmentInAssociate" xlink:title="999023 - Disclosure - INVESTMENT IN AN ASSOCIATE" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/LongTermPrepayment" xlink:title="999024 - Disclosure - LONG TERM PREPAYMENT" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AccountsPayable" xlink:title="999025 - Disclosure - ACCOUNTS PAYABLE" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AmountDueToRelatedCompanies" xlink:title="999026 - Disclosure - AMOUNT DUE TO RELATED COMPANIES" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AmountDueToDirectors" xlink:title="999027 - Disclosure - AMOUNT DUE TO DIRECTORS" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/NotesPayable" xlink:title="999028 - Disclosure - NOTES PAYABLE" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/CommitmentsAndContingencies" xlink:title="999029 - Disclosure - COMMITMENTS AND CONTINGENCIES" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/StockholdersEquity" xlink:title="999030 - Disclosure - STOCKHOLDERS&#8217; EQUITY" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/RelatedPartyTransactions" xlink:title="999031 - Disclosure - RELATED PARTY TRANSACTIONS" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/NetLossPerOrdinaryShare" xlink:title="999032 - Disclosure - NET LOSS PER ORDINARY SHARE" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/Revenue" xlink:title="999033 - Disclosure - REVENUE" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/IncomeTaxes" xlink:title="999034 - Disclosure - INCOME TAXES" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/SubsequentEvents" xlink:title="999035 - Disclosure - SUBSEQUENT EVENTS" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/SummaryOfSignificantAccountingPoliciesPolicies" xlink:title="999036 - Disclosure - SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/SubsidiariesTables" xlink:title="999037 - Disclosure - SUBSIDIARIES (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AccountsReceivableTables" xlink:title="999038 - Disclosure - ACCOUNTS RECEIVABLE (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/ContractLiabilitiesTables" xlink:title="999039 - Disclosure - CONTRACT LIABILITIES (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/PrepaidExpensesAndOtherCurrentAssetsNetTables" xlink:title="999040 - Disclosure - PREPAID EXPENSES AND OTHER CURRENT ASSETS, NET (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/EquipmentNetTables" xlink:title="999041 - Disclosure - EQUIPMENT, NET (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/InvestmentInAssociateTables" xlink:title="999042 - Disclosure - INVESTMENT IN AN ASSOCIATE (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AccountsPayableTables" xlink:title="999043 - Disclosure - ACCOUNTS PAYABLE (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AmountDueToRelatedCompaniesTables" xlink:title="999044 - Disclosure - AMOUNT DUE TO RELATED COMPANIES (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/NotesPayableTables" xlink:title="999045 - Disclosure - NOTES PAYABLE (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/RelatedPartyTransactionsTables" xlink:title="999046 - Disclosure - RELATED PARTY TRANSACTIONS (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/NetLossPerOrdinaryShareTables" xlink:title="999047 - Disclosure - NET LOSS PER ORDINARY SHARE (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/RevenueTables" xlink:title="999048 - Disclosure - REVENUE (Tables)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/OrganizationAndPrincipalActivitiesDetailsNarrative" xlink:title="999049 - Disclosure - ORGANIZATION AND PRINCIPAL ACTIVITIES (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncashOrPartNoncashAcquisitionsLineItems" xlink:label="loc_us-gaapNoncashOrPartNoncashAcquisitionsLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncashOrPartNoncashAcquisitionsTable" xlink:label="loc_us-gaapNoncashOrPartNoncashAcquisitionsTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapNoncashOrPartNoncashAcquisitionsLineItems" xlink:to="loc_us-gaapNoncashOrPartNoncashAcquisitionsTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncashOrPartNoncashAcquisitionsByUniqueDescriptionAxis" xlink:label="loc_us-gaapNoncashOrPartNoncashAcquisitionsByUniqueDescriptionAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapNoncashOrPartNoncashAcquisitionsTable" xlink:to="loc_us-gaapNoncashOrPartNoncashAcquisitionsByUniqueDescriptionAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncashOrPartNoncashAcquisitionNameDomain" xlink:label="loc_us-gaapNoncashOrPartNoncashAcquisitionNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapNoncashOrPartNoncashAcquisitionsByUniqueDescriptionAxis" xlink:to="loc_us-gaapNoncashOrPartNoncashAcquisitionNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NoncashOrPartNoncashAcquisitionNameDomain" xlink:label="loc_us-gaapNoncashOrPartNoncashAcquisitionNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapNoncashOrPartNoncashAcquisitionsByUniqueDescriptionAxis" xlink:to="loc_us-gaapNoncashOrPartNoncashAcquisitionNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ModuLinkInvestmentLimitedMember" xlink:label="loc_MDLKModuLinkInvestmentLimitedMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapNoncashOrPartNoncashAcquisitionNameDomain" xlink:to="loc_MDLKModuLinkInvestmentLimitedMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockholdersEquityOtherShares" xlink:label="loc_us-gaapStockholdersEquityOtherShares_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapNoncashOrPartNoncashAcquisitionsLineItems" xlink:to="loc_us-gaapStockholdersEquityOtherShares_40" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaapNetIncomeLoss_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapNoncashOrPartNoncashAcquisitionsLineItems" xlink:to="loc_us-gaapNetIncomeLoss_40" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaapNetCashProvidedByUsedInOperatingActivities_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapNoncashOrPartNoncashAcquisitionsLineItems" xlink:to="loc_us-gaapNetCashProvidedByUsedInOperatingActivities_40" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RetainedEarningsAccumulatedDeficit" xlink:label="loc_us-gaapRetainedEarningsAccumulatedDeficit_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapNoncashOrPartNoncashAcquisitionsLineItems" xlink:to="loc_us-gaapRetainedEarningsAccumulatedDeficit_40" xlink:type="arc" order="3" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/SubsidiariesDetails" xlink:title="999050 - Disclosure - SUBSIDIARIES (Details)">
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_DisclosureLineElements" xlink:label="loc_MDLKDisclosureLineElements" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_DisclosureTable" xlink:label="loc_MDLKDisclosureTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_MDLKDisclosureTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_srtScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_MDLKDisclosureTable" xlink:to="loc_srtScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srtEquityMethodInvesteeNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="loc_srtEquityMethodInvesteeNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srtEquityMethodInvesteeNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="loc_srtEquityMethodInvesteeNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ModuLinkInvestmentLimitedMember" xlink:label="loc_MDLKModuLinkInvestmentLimitedMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtEquityMethodInvesteeNameDomain" xlink:to="loc_MDLKModuLinkInvestmentLimitedMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ModuLinkCorporationLimitedMember" xlink:label="loc_MDLKModuLinkCorporationLimitedMember_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtEquityMethodInvesteeNameDomain" xlink:to="loc_MDLKModuLinkCorporationLimitedMember_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ZenithIntegratedModularLimitedMember" xlink:label="loc_MDLKZenithIntegratedModularLimitedMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtEquityMethodInvesteeNameDomain" xlink:to="loc_MDLKZenithIntegratedModularLimitedMember_60" xlink:type="arc" order="61" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ZenithAYModularBuildingsCompanyLimitedMember" xlink:label="loc_MDLKZenithAYModularBuildingsCompanyLimitedMember_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtEquityMethodInvesteeNameDomain" xlink:to="loc_MDLKZenithAYModularBuildingsCompanyLimitedMember_90" xlink:type="arc" order="91" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ModuLinkInnTechLimitedMember" xlink:label="loc_MDLKModuLinkInnTechLimitedMember_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtEquityMethodInvesteeNameDomain" xlink:to="loc_MDLKModuLinkInnTechLimitedMember_120" xlink:type="arc" order="121" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ModuLinkInnoTechCompanyLimitedMember" xlink:label="loc_MDLKModuLinkInnoTechCompanyLimitedMember_150" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtEquityMethodInvesteeNameDomain" xlink:to="loc_MDLKModuLinkInnoTechCompanyLimitedMember_150" xlink:type="arc" order="151" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_PlaceOfIncorporation" xlink:label="loc_MDLKPlaceOfIncorporation_190" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_MDLKPlaceOfIncorporation_190" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaapEquityMethodInvestmentOwnershipPercentage_190" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapEquityMethodInvestmentOwnershipPercentage_190" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentDescriptionOfPrincipalActivities" xlink:label="loc_us-gaapEquityMethodInvestmentDescriptionOfPrincipalActivities_190" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapEquityMethodInvestmentDescriptionOfPrincipalActivities_190" xlink:type="arc" order="2" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AccountsReceivableDetails" xlink:title="999051 - Disclosure - ACCOUNTS RECEIVABLE (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AccountsReceivableDetailsNarrative" xlink:title="999052 - Disclosure - ACCOUNTS RECEIVABLE (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/ContractAssetsAndLiabilitiesDetails-ContractLiabilities" xlink:title="999053 - Disclosure - CONTRACT ASSETS AND LIABILITIES (Details - Contract liabilities)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/PrepaidExpensesAndOtherCurrentAssetsNetDetails" xlink:title="999054 - Disclosure - PREPAID EXPENSES AND OTHER CURRENT ASSETS, NET (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/LoanReceivablesDetailsNarrative" xlink:title="999055 - Disclosure - LOAN RECEIVABLES (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/EquipmentNetDetails" xlink:title="999056 - Disclosure - EQUIPMENT, NET (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaapPropertyPlantAndEquipmentLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaapScheduleOfPropertyPlantAndEquipmentTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapPropertyPlantAndEquipmentLineItems" xlink:to="loc_us-gaapScheduleOfPropertyPlantAndEquipmentTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfPropertyPlantAndEquipmentTable" xlink:to="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" xlink:to="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaapPropertyPlantAndEquipmentTypeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapPropertyPlantAndEquipmentByTypeAxis" xlink:to="loc_us-gaapPropertyPlantAndEquipmentTypeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OfficeEquipmentMember" xlink:label="loc_us-gaapOfficeEquipmentMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:to="loc_us-gaapOfficeEquipmentMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ComputerEquipmentMember" xlink:label="loc_us-gaapComputerEquipmentMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:to="loc_us-gaapComputerEquipmentMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaapFurnitureAndFixturesMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:to="loc_us-gaapFurnitureAndFixturesMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="loc_us-gaapLeaseholdImprovementsMember_60" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentTypeDomain" xlink:to="loc_us-gaapLeaseholdImprovementsMember_60" xlink:type="arc" order="61" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="loc_us-gaapPropertyPlantAndEquipmentGross_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentLineItems" xlink:to="loc_us-gaapPropertyPlantAndEquipmentGross_110" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="loc_us-gaapAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentLineItems" xlink:to="loc_us-gaapAccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_110" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="loc_us-gaapPropertyPlantAndEquipmentNet_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPropertyPlantAndEquipmentLineItems" xlink:to="loc_us-gaapPropertyPlantAndEquipmentNet_110" xlink:type="arc" order="2" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/EquipmentNetDetailsNarrative" xlink:title="999057 - Disclosure - EQUIPMENT, NET (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/InvestmentInAssociateDetails" xlink:title="999058 - Disclosure - INVESTMENT IN AN ASSOCIATE (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/InvestmentInAssociateDetails-FinancialInformation" xlink:title="999059 - Disclosure - INVESTMENT IN AN ASSOCIATE (Details - Financial Information)">
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_DisclosureLineElements" xlink:label="loc_MDLKDisclosureLineElements" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_DisclosureTable" xlink:label="loc_MDLKDisclosureTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_MDLKDisclosureTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountAxis" xlink:label="loc_us-gaapPartnerTypeOfPartnersCapitalAccountAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_MDLKDisclosureTable" xlink:to="loc_us-gaapPartnerTypeOfPartnersCapitalAccountAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaapPartnerTypeOfPartnersCapitalAccountNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapPartnerTypeOfPartnersCapitalAccountAxis" xlink:to="loc_us-gaapPartnerTypeOfPartnersCapitalAccountNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PartnerTypeOfPartnersCapitalAccountNameDomain" xlink:label="loc_us-gaapPartnerTypeOfPartnersCapitalAccountNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapPartnerTypeOfPartnersCapitalAccountAxis" xlink:to="loc_us-gaapPartnerTypeOfPartnersCapitalAccountNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_OwnershipControlInterestMember" xlink:label="loc_MDLKOwnershipControlInterestMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapPartnerTypeOfPartnersCapitalAccountNameDomain" xlink:to="loc_MDLKOwnershipControlInterestMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsNoncurrent" xlink:label="loc_us-gaapAssetsNoncurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapAssetsNoncurrent_50" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AssetsCurrent" xlink:label="loc_us-gaapAssetsCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapAssetsCurrent_50" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesNoncurrent" xlink:label="loc_us-gaapLiabilitiesNoncurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapLiabilitiesNoncurrent_50" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_LiabilitiesCurrent" xlink:label="loc_us-gaapLiabilitiesCurrent_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapLiabilitiesCurrent_50" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_NetLiabilities" xlink:label="loc_MDLKNetLiabilities_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_MDLKNetLiabilities_50" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherLiabilities" xlink:label="loc_us-gaapOtherLiabilities_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapOtherLiabilities_50" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues" xlink:label="loc_us-gaapRevenues_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapRevenues_50" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_IncomeLossFromContinuingOperations" xlink:label="loc_us-gaapIncomeLossFromContinuingOperations_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapIncomeLossFromContinuingOperations_50" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTax" xlink:label="loc_us-gaapOtherComprehensiveIncomeLossBeforeTax_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapOtherComprehensiveIncomeLossBeforeTax_50" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossTax" xlink:label="loc_us-gaapOtherComprehensiveIncomeLossTax_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapOtherComprehensiveIncomeLossTax_50" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax" xlink:label="loc_us-gaapOtherComprehensiveIncomeLossNetOfTax_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_MDLKDisclosureLineElements" xlink:to="loc_us-gaapOtherComprehensiveIncomeLossNetOfTax_50" xlink:type="arc" order="10" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AccountsPayableDetails" xlink:title="999060 - Disclosure - ACCOUNTS PAYABLE (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AccountsPayableDetailsNarrative" xlink:title="999061 - Disclosure - ACCOUNTS PAYABLE (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaapRelatedPartyTransactionLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaapScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_us-gaapScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAxis" xlink:label="loc_us-gaapRelatedPartyTransactionAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="loc_us-gaapRelatedPartyTransactionAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaapRelatedPartyTransactionDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionAxis" xlink:to="loc_us-gaapRelatedPartyTransactionDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionDomain" xlink:label="loc_us-gaapRelatedPartyTransactionDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionAxis" xlink:to="loc_us-gaapRelatedPartyTransactionDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_RelatedCompanyPayableMember" xlink:label="loc_MDLKRelatedCompanyPayableMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionDomain" xlink:to="loc_MDLKRelatedCompanyPayableMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_AccountsPayableCurrent" xlink:label="loc_us-gaapAccountsPayableCurrent_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_us-gaapAccountsPayableCurrent_30" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/AmountDueToRelatedCompaniesDetails" xlink:title="999062 - Disclosure - AMOUNT DUE TO RELATED COMPANIES (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems" xlink:label="loc_us-gaapDefinedBenefitPlanDisclosureLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:label="loc_us-gaapScheduleOfDefinedBenefitPlansDisclosuresTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapDefinedBenefitPlanDisclosureLineItems" xlink:to="loc_us-gaapScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ZenithPMSLimitedMember" xlink:label="loc_MDLKZenithPMSLimitedMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_MDLKZenithPMSLimitedMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_AYConsultingServicesCompanyMember" xlink:label="loc_MDLKAYConsultingServicesCompanyMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_MDLKAYConsultingServicesCompanyMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_AmountDueToRelatedPartiesCurrent" xlink:label="loc_MDLKAmountDueToRelatedPartiesCurrent_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDefinedBenefitPlanDisclosureLineItems" xlink:to="loc_MDLKAmountDueToRelatedPartiesCurrent_70" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/NotesPayableDetails" xlink:title="999063 - Disclosure - NOTES PAYABLE (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtLineItems" xlink:label="loc_us-gaapShortTermDebtLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShortTermDebtTable" xlink:label="loc_us-gaapScheduleOfShortTermDebtTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapScheduleOfShortTermDebtTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaapDebtInstrumentAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfShortTermDebtTable" xlink:to="loc_us-gaapDebtInstrumentAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ZenithHongKongEngineeringLimitedMember" xlink:label="loc_MDLKZenithHongKongEngineeringLimitedMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_MDLKZenithHongKongEngineeringLimitedMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ZenithHongKongEngineeringLimited1Member" xlink:label="loc_MDLKZenithHongKongEngineeringLimited1Member_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_MDLKZenithHongKongEngineeringLimited1Member_30" xlink:type="arc" order="31" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaapDebtInstrumentFaceAmount_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDebtInstrumentFaceAmount_90" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentIssuanceDate1" xlink:label="loc_us-gaapDebtInstrumentIssuanceDate1_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDebtInstrumentIssuanceDate1_90" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_NotesPayableCurrent" xlink:label="loc_us-gaapNotesPayableCurrent_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapNotesPayableCurrent_90" xlink:type="arc" order="2" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/NotesPayableDetailsNarrative" xlink:title="999064 - Disclosure - NOTES PAYABLE (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ShortTermDebtLineItems" xlink:label="loc_us-gaapShortTermDebtLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfShortTermDebtTable" xlink:label="loc_us-gaapScheduleOfShortTermDebtTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapScheduleOfShortTermDebtTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaapDebtInstrumentAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfShortTermDebtTable" xlink:to="loc_us-gaapDebtInstrumentAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaapDebtInstrumentNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapDebtInstrumentAxis" xlink:to="loc_us-gaapDebtInstrumentNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ZenithHKNotesMember" xlink:label="loc_MDLKZenithHKNotesMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_MDLKZenithHKNotesMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ZenithHKNotes1Member" xlink:label="loc_MDLKZenithHKNotes1Member_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDebtInstrumentNameDomain" xlink:to="loc_MDLKZenithHKNotes1Member_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaapDebtInstrumentFaceAmount_30" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapShortTermDebtLineItems" xlink:to="loc_us-gaapDebtInstrumentFaceAmount_30" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/CommitmentsAndContingenciesDetailsNarrative" xlink:title="999065 - Disclosure - COMMITMENTS AND CONTINGENCIES (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/StockholdersEquityDetailsNarrative" xlink:title="999066 - Disclosure - STOCKHOLDERS&#8217; EQUITY (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockLineItems" xlink:label="loc_us-gaapClassOfStockLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfStockByClassTable" xlink:label="loc_us-gaapScheduleOfStockByClassTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapScheduleOfStockByClassTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaapStatementClassOfStockAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfStockByClassTable" xlink:to="loc_us-gaapStatementClassOfStockAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaapClassOfStockDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapStatementClassOfStockAxis" xlink:to="loc_us-gaapClassOfStockDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaapCommonStockMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapCommonStockMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_SeriesAConvertiblePreferredSharesMember" xlink:label="loc_MDLKSeriesAConvertiblePreferredSharesMember_70" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_MDLKSeriesAConvertiblePreferredSharesMember_70" xlink:type="arc" order="71" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_SeriesAConvertiblePreferredStockMember" xlink:label="loc_MDLKSeriesAConvertiblePreferredStockMember_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_MDLKSeriesAConvertiblePreferredStockMember_110" xlink:type="arc" order="111" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockMember" xlink:label="loc_us-gaapPreferredStockMember_120" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockDomain" xlink:to="loc_us-gaapPreferredStockMember_120" xlink:type="arc" order="121" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_srtScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfStockByClassTable" xlink:to="loc_srtScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srtEquityMethodInvesteeNameDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="loc_srtEquityMethodInvesteeNameDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srtEquityMethodInvesteeNameDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:to="loc_srtEquityMethodInvesteeNameDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ModuLinkInvestmentLimitedMember" xlink:label="loc_MDLKModuLinkInvestmentLimitedMember_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtEquityMethodInvesteeNameDomain" xlink:to="loc_MDLKModuLinkInvestmentLimitedMember_50" xlink:type="arc" order="51" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaapSubsequentEventTypeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfStockByClassTable" xlink:to="loc_us-gaapSubsequentEventTypeAxis" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaapSubsequentEventTypeDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapSubsequentEventTypeAxis" xlink:to="loc_us-gaapSubsequentEventTypeDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaapSubsequentEventTypeDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapSubsequentEventTypeAxis" xlink:to="loc_us-gaapSubsequentEventTypeDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SubsequentEventMember" xlink:label="loc_us-gaapSubsequentEventMember_110" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSubsequentEventTypeDomain" xlink:to="loc_us-gaapSubsequentEventMember_110" xlink:type="arc" order="112" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CapitalUnitsAuthorized" xlink:label="loc_us-gaapCapitalUnitsAuthorized_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapCapitalUnitsAuthorized_140" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaapCommonStockSharesAuthorized_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapCommonStockSharesAuthorized_140" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockParOrStatedValuePerShare" xlink:label="loc_us-gaapCommonStockParOrStatedValuePerShare_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapCommonStockParOrStatedValuePerShare_140" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesAuthorized" xlink:label="loc_us-gaapPreferredStockSharesAuthorized_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapPreferredStockSharesAuthorized_140" xlink:type="arc" order="3" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockParOrStatedValuePerShare" xlink:label="loc_us-gaapPreferredStockParOrStatedValuePerShare_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapPreferredStockParOrStatedValuePerShare_140" xlink:type="arc" order="4" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesIssued" xlink:label="loc_us-gaapCommonStockSharesIssued_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapCommonStockSharesIssued_140" xlink:type="arc" order="5" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_CommonStockSharesOutstanding" xlink:label="loc_us-gaapCommonStockSharesOutstanding_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapCommonStockSharesOutstanding_140" xlink:type="arc" order="6" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaapEquityMethodInvestmentOwnershipPercentage_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapEquityMethodInvestmentOwnershipPercentage_140" xlink:type="arc" order="7" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodSharesAcquisitions" xlink:label="loc_us-gaapStockIssuedDuringPeriodSharesAcquisitions_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodSharesAcquisitions_140" xlink:type="arc" order="8" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SharesIssuedPricePerShare" xlink:label="loc_us-gaapSharesIssuedPricePerShare_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapSharesIssuedPricePerShare_140" xlink:type="arc" order="9" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_StockIssuedDuringPeriodValueAcquisitions" xlink:label="loc_us-gaapStockIssuedDuringPeriodValueAcquisitions_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapStockIssuedDuringPeriodValueAcquisitions_140" xlink:type="arc" order="10" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesIssued" xlink:label="loc_us-gaapPreferredStockSharesIssued_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapPreferredStockSharesIssued_140" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockSharesOutstanding" xlink:label="loc_us-gaapPreferredStockSharesOutstanding_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapPreferredStockSharesOutstanding_140" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_PreferredStockVotingRights" xlink:label="loc_us-gaapPreferredStockVotingRights_140" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapClassOfStockLineItems" xlink:to="loc_us-gaapPreferredStockVotingRights_140" xlink:type="arc" order="13" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/RelatedPartyTransactionsDetails" xlink:title="999067 - Disclosure - RELATED PARTY TRANSACTIONS (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionLineItems" xlink:label="loc_us-gaapRelatedPartyTransactionLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:label="loc_us-gaapScheduleOfRelatedPartyTransactionsByRelatedPartyTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_us-gaapScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapScheduleOfRelatedPartyTransactionsByRelatedPartyTable" xlink:to="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyDomain" xlink:label="loc_us-gaapRelatedPartyDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_us-gaapRelatedPartyTransactionsByRelatedPartyAxis" xlink:to="loc_us-gaapRelatedPartyDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ProjectAndDesignManagementServiceFeesPaidToZenithPMSLimitedMember" xlink:label="loc_MDLKProjectAndDesignManagementServiceFeesPaidToZenithPMSLimitedMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_MDLKProjectAndDesignManagementServiceFeesPaidToZenithPMSLimitedMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_ProductDevelopmentFeesPaidToLeidenfordLtdMember" xlink:label="loc_MDLKProductDevelopmentFeesPaidToLeidenfordLtdMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyDomain" xlink:to="loc_MDLKProductDevelopmentFeesPaidToLeidenfordLtdMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_RelatedPartyTransactionAmountsOfTransaction" xlink:label="loc_us-gaapRelatedPartyTransactionAmountsOfTransaction_50" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapRelatedPartyTransactionLineItems" xlink:to="loc_us-gaapRelatedPartyTransactionAmountsOfTransaction_50" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/RelatedPartyTransactionsDetailsNarrative" xlink:title="999068 - Disclosure - RELATED PARTY TRANSACTIONS (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/NetLossPerOrdinaryShareDetails" xlink:title="999069 - Disclosure - NET LOSS PER ORDINARY SHARE (Details)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/RevenueDetails" xlink:title="999070 - Disclosure - REVENUE (Details)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueLineItems" xlink:label="loc_us-gaapDisaggregationOfRevenueLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_DisaggregationOfRevenueTable" xlink:label="loc_us-gaapDisaggregationOfRevenueTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapDisaggregationOfRevenueLineItems" xlink:to="loc_us-gaapDisaggregationOfRevenueTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srtProductOrServiceAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapDisaggregationOfRevenueTable" xlink:to="loc_srtProductOrServiceAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srtProductsAndServicesDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtProductOrServiceAxis" xlink:to="loc_srtProductsAndServicesDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_DesignAndBuildServicesMember" xlink:label="loc_MDLKDesignAndBuildServicesMember_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_MDLKDesignAndBuildServicesMember_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_ManagementServiceMember" xlink:label="loc_us-gaapManagementServiceMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_us-gaapManagementServiceMember_20" xlink:type="arc" order="21" />
      <link:loc xlink:type="locator" xlink:href="mdlk-20260331.xsd#MDLK_SalesOfGoodsMember" xlink:label="loc_MDLKSalesOfGoodsMember_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtProductsAndServicesDomain" xlink:to="loc_MDLKSalesOfGoodsMember_40" xlink:type="arc" order="41" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_Revenues" xlink:label="loc_us-gaapRevenues_90" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapDisaggregationOfRevenueLineItems" xlink:to="loc_us-gaapRevenues_90" xlink:type="arc" order="0" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/IncomeTaxesDetailsNarrative" xlink:title="999071 - Disclosure - INCOME TAXES (Details Narrative)">
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleLineItems" xlink:label="loc_us-gaapSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleLineItems" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleTable" xlink:label="loc_us-gaapSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleTable" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xbrldt:contextElement="segment" xlink:from="loc_us-gaapSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleLineItems" xlink:to="loc_us-gaapSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleTable" xlink:type="arc" order="10" xbrldt:closed="true" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_StatementGeographicalAxis" xlink:label="loc_srtStatementGeographicalAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleTable" xlink:to="loc_srtStatementGeographicalAxis" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srtSegmentGeographicalDomain" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtStatementGeographicalAxis" xlink:to="loc_srtSegmentGeographicalDomain" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_SegmentGeographicalDomain" xlink:label="loc_srtSegmentGeographicalDomain_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtStatementGeographicalAxis" xlink:to="loc_srtSegmentGeographicalDomain_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/stpr/2026/stpr-2026.xsd#stpr_NV" xlink:label="loc_stprNV_0" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtSegmentGeographicalDomain" xlink:to="loc_stprNV_0" xlink:type="arc" order="1" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.sec.gov/country/2026/country-2026.xsd#country_HK" xlink:label="loc_countryHK_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtSegmentGeographicalDomain" xlink:to="loc_countryHK_10" xlink:type="arc" order="11" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeAxis" xlink:label="loc_srtRangeAxis" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaapSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleTable" xlink:to="loc_srtRangeAxis" xlink:type="arc" order="2" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember" xlink:type="arc" order="20" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_RangeMember" xlink:label="loc_srtRangeMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xbrldt:contextElement="segment" xlink:from="loc_srtRangeAxis" xlink:to="loc_srtRangeMember_10" xlink:type="arc" order="30" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MinimumMember" xlink:label="loc_srtMinimumMember_10" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMinimumMember_10" xlink:type="arc" order="12" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/srt/2026/elts/srt-2026.xsd#srt_MaximumMember" xlink:label="loc_srtMaximumMember_20" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srtRangeMember" xlink:to="loc_srtMaximumMember_20" xlink:type="arc" order="22" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="loc_us-gaapEffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleLineItems" xlink:to="loc_us-gaapEffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_40" xlink:type="arc" order="0" />
      <link:loc xlink:type="locator" xlink:href="https://xbrl.fasb.org/us-gaap/2026/elts/us-gaap-2026.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="loc_us-gaapEffectiveIncomeTaxRateContinuingOperations_40" />
      <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaapSignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleLineItems" xlink:to="loc_us-gaapEffectiveIncomeTaxRateContinuingOperations_40" xlink:type="arc" order="1" />
    </link:definitionLink>
    <link:definitionLink xlink:type="extended" xlink:role="http://modulinktech.com/role/SegmentReportingDetailsNarrative" xlink:title="999072 - Disclosure - Segment Reporting (Details Narrative)" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/ecd/role/PvpExecutiveCategoriesOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/ecd/role/PvpAdjustmentsOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/ecd/role/IndividualsOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/ecd/AwardTypeOnly" />
    <link:definitionLink xlink:type="extended" xlink:role="http://xbrl.sec.gov/ecd/role/TradingArrangementsOnly" />
</link:linkbase>
