late 14c., jowe, joue, "the bones of the mouth," "A word of difficult etymology" [OED]. Probably from Old French joue "cheek," originally jode, from Gallo-Romance *gauta or directly from Gaulish *gabata, but there are phonetic problems; or perhaps a variant of Germanic words related to chew (v.); compare also the two nouns jowl. Replaced Old English ceace, ceafl. Jaws as "holding and gripping part of an appliance" is from mid-15c.; figuratively, of time, death, defeat, etc., from 1560s.