Mandible /(?)/

Man·di·ble

Mandible

n.
  1. The bone, or principal bone, of the lower jaw; the inferior maxilla; -- also applied to either the upper or the lower jaw in the beak of birds. (Anat.)
  2. The anterior pair of mouth organs of insects, crustaceaus, and related animals, whether adapted for biting or not. See Illust. of Diptera. (Zool.)