Pronunciation enPR: kōʹ (UK) IPA (key): /ˈkəʊ-/ (US) IPA (key): /ˈkoʊ-/ (AU) IPA (key): /ˈkəʉ-/ Prefix Prefixco- co- is a prefix added to verbs and means that something is done together or mutually. Wikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads