* Inferior bone of the jaw (lower jaw, lower jaw bone.
* In vertebrates, it articulates with the cranium. When the mouth is closed, an interlocking system of processes prevents lateral, and usually, backward movement; but allows the jaw to be depressed to open the mouth (hinge joint-like action), and in mammals to be advanced slightly on the cranium by a gliding movement.
* In humans and certain other species that chew food, one large tooth-bearing bone on each side.