The Collaborative International Dictionary of English v.0.48:

Chin \Chin\ (ch[i^]n), 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.
      [1913 Webster]

   2. (Zool.) The exterior or under surface embraced between the
      branches of the lower jaw bone, in birds.
      [1913 Webster]

WordNet (r) 3.0 (2006):

chin
    n 1: the protruding part of the lower jaw [syn: chin,
         mentum]
    2: Kamarupan languages spoken in western Burma and Bangladesh
       and easternmost India [syn: Kuki, Chin, Kuki-Chin]
    v 1: raise oneself while hanging from one's hands until one's
         chin is level with the support bar [syn: chin, chin up]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "chin":
   bandy words, bat the breeze, beat the gums, button, causerie, chat,
   chew the fat, chew the rag, colloque, colloquize, commerce with,
   commune with, communicate, communicate with, confab, confabulate,
   converse, converse with, discourse with, jaw, mentum, prose, rap,
   shoot the breeze, speak with, spiel, take counsel with, talk,
   talk together, visit, visit with, yak, yakkety-yak, yap, yarn