Entry 1 sense Webster, 1913 Heterogeneity /hĕtˌ-ẽr-əj-ĭn-ē'-ət-ē/ · Het·er·o·ge·ne·i·ty · IPA /hˌɛtərədʒɪnˈiːətiː/ 01 n. The state of being heterogeneous; contrariety. 1. The state of being heterogeneous; contrariety. “The difference, indeed the heterogeneity, of the two may be felt.” — Coleridge.