Definition of "tooth" []

• One of a set of hard, bonelike structures rooted in sockets in the jaws of vertebrates, typically composed of a core of soft pulp surrounded by a layer of hard dentin that is coated with cementum or enamel at the crown and used for biting or chewing food or as a means of attack or defense. (noun)
• A similar structure in invertebrates, such as one of the pointed denticles or ridges on the exoskeleton of an arthropod or the shell of a mollusk. (noun)
• A projecting part resembling a tooth in shape or function, as on a comb, gear, or saw. (noun)
• A small, notched projection along a margin, especially of a leaf. Also called dent2. (noun)
• A rough surface, as of paper or metal. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "To fight “tooth and nail” is to fight with the intensity and ferocity of a wild animal: “The resistance forces fought the invading troops tooth and nail."
• "An adaptation of a command of Jesus in the Sermon on the Mount: “Ye have heard that it hath been said, “An eye for an eye, and a tooth for a tooth”; but I say unto you, that ye resist not evil: but whosoever shall smite thee on thy right cheek, turn to him the other also."
• "False tooth A ‘tooth’ made of plastic or other material, used to replace a tooth that has been taken out."