chin: [OE] Chin has relatives throughout the Germanic languages (German has kinn, for instance, and Dutch kin) and is also represented in words for ‘lower jaw’, ‘mouth’, ‘cheek’, etc in other Indo-European languages (Greek gnáthos ‘jaw’, for example, which gave English prognathous ‘having projecting jaws’). All go back to a prehistoric Indo-European source *genw-. => prognathous[chin etymology, chin origin, 英语词源]