1N-COUNT (人、动物的)下颌骨 A mandible is the bone in the lower jaw of a person or animal. (人、动物的)下颌骨 [technical]
2N-COUNT [usually plural](昆虫的)颚 An insect's mandibles are the two parts of its mouth which it uses for biting, similar to an animal's jaws. (昆虫的)颚 [technical]