Chin \Chin\, n. [AS. cin, akin to OS. kin, G kinn, Icel. kinn, cheek, Dan. & Sw. kind, L. gena, Gr. ?; cf. Skr. hanu. [root]232.]

1. The lower extremity of the face below the mouth; the point of the under jaw.

2. (Zo["o]l.) The exterior or under surface embraced between the branches of the lower jaw bone, in birds.

Source: Webster's Revised Unabridged Dictionary (1913)