Entry 1 sense Webster, 1913 Subfamily /sŭb'-fămˌ-əl-ē/ · Sub·fam·i·ly · IPA /sˈʌbfˌæməliː/ 01 n. One of the subdivisions, of more importance than genus, into which certain families are divided. 1. One of the subdivisions, of more importance than genus, into which certain families are divided.(Biol.)