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Old English cin, cinn "chin" (but in some compounds suggesting an older, broader sense of "jawbone"); a general Germanic word (cf. Old Saxon and Old High German kinni; Old Norse kinn; German Kinn "chin;" Gothic kinnus "cheek"), from PIE root *genu- "chin, jawbone" (cf. Sanskrit hanuh, Avestan zanu- "chin;" Armenian cnawt "jawbone, cheek;" Lithuanian žándas "jawbone;" Greek genus "lower jaw," geneion "chin;" Old Irish gin "mouth," Welsh gen "jawbone, chin").
1590s, "to press (affectionately) chin to chin," from chin (n.). Meaning "to bring to the chin" (of a fiddle) is from 1869. Slang meaning "talk, gossip" is from 1883, American English. Related: Chinned; chinning. Athletic sense of "raise one's chin over" (a raised bar, for exercise) is from 1880s.
The prominence formed by the anterior projection of the lower jaw.