Chin

1. n. The exterior or under surface embraced between the branches of the lower jaw bone, in birds.
2. n. The lower extremity of the face below the mouth; the point of the under jaw.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.