Chin (chĭn), n. [AS. cin, akin to OS. kin, G kinn, Icel. kinn, cheek, Dan. & Sw. kind, L. gena, Gr. �; cf. Skr. hanu. √232.] 1. The lower extremity of the face below the mouth; the point of the under jaw.
2. (Zoöl.) The exterior or under surface embraced between the branches of the lower jaw bone, in birds.