post·fix I. \ˈ ̷ ̷ˌ ̷ ̷\noun (-es) Etymology:post- + -fix (as in prefix) : a letter, syllable, or word added to the end of another word : suffix II. \(ˈ) ̷ ̷| ̷ ̷\transitive verb : to affix at the end; specifically: to add (a letter or syllable) to the end of a word