The term JAW, LOWER is composed of two words: MANDIBLE (8 letters) and CHIN (4 letters). The MANDIBLE, also known as the lower jaw, is a U-shaped bone that forms the lower part of the face. It is the only movable bone in the skull and is connected to the temporal bones by muscles and ligaments. The CHIN is the lowermost part of the face, located at the bottom of the MANDIBLE. It is made up of a triangular-shaped bone called the mental protuberance, which is connected to the MANDIBLE by a ligament.