tooth

(noun) hard bonelike structures in the jaws of vertebrates; used for biting and chewing or for attack and defense.

(noun) something resembling the tooth of an animal.

(noun) toothlike structure in invertebrates found in the mouth or alimentary canal or on a shell.

(noun) a means of enforcement. Example: "The treaty had no teeth in it."

(noun) one of a number of uniform projections on a gear.