Each of the hard, bone-like things in your mouth, the ones you use for chewing food, is called a tooth. When you lost your first tooth, you probably put it under your pillow in the hopes that the Tooth Fairy would come and leave you a surprise.

Teeth are as hard as bone, but they're actually made of layers of very dense tissue, with enamel on the outside. Humans lose their original set of teeth when they're children, growing new ones to replace them, while sharks grow an entirely new set every two weeks. Something is also called a tooth when it resembles animal teeth, like the teeth of a saw or a gear. When you fight tooth and nail, you fight fiercely.

Definitions of tooth
  1. noun
    hard bonelike structures in the jaws of vertebrates; used for biting and chewing or for attack and defense
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    hollow or grooved tooth of a venomous snake; used to inject its poison
    a long pointed tooth specialized for fighting or digging; especially in an elephant or walrus or hog
    the tiny fossil cone-shaped tooth of a primitive vertebrate of order Conodonta
    chopper, pearly
    informal terms for a human `tooth'
    carnassial tooth
    the last upper premolar and first lower molar teeth of a carnivore; having sharp edges for cutting flesh
    anterior, front tooth
    a tooth situated at the front of the mouth
    back tooth, posterior
    a tooth situated at the back of the mouth
    malposed tooth
    a tooth that has grown in a faulty position
    adult tooth, permanent tooth
    any of the 32 teeth that replace the deciduous teeth of early childhood and (with luck) can last until old age
    baby tooth, deciduous tooth, milk tooth, primary tooth
    one of the first temporary teeth of a young mammal (one of 20 in children)
    canine, canine tooth, cuspid, dogtooth, eye tooth, eyetooth
    one of the four pointed conical teeth (two in each jaw) located between the incisors and the premolars
    bicuspid, premolar
    a tooth having two cusps or points; located between the incisors and the molars
    a tooth for cutting or gnawing; located in the front of the mouth in both jaws
    grinder, molar
    grinding tooth with a broad crown; located behind the premolars
    canine tooth of a carnivorous animal; used to seize and tear its prey
    a large projecting front tooth
    wisdom tooth
    any of the last 4 teeth on each side of the upper and lower jaw; the last of the permanent teeth to erupt (between ages 16 and 21)
    type of:
    bone, os
    rigid connective tissue that makes up the skeleton of vertebrates
  2. noun
    toothlike structure in invertebrates found in the mouth or alimentary canal or on a shell
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    small pointed ridge on the exoskeleton of an arthropod
    type of:
    anatomical structure, bodily structure, body structure, complex body part, structure
    a particular complex anatomical part of a living thing
  3. noun
    something resembling the tooth of an animal
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    cog, sprocket
    tooth on the rim of gear wheel
    type of:
    any structure that branches out from a central support
  4. noun
    one of a number of uniform projections on a gear
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    type of:
    any structure that branches out from a central support
  5. noun
    a means of enforcement
    “the treaty had no teeth in it”
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    type of:
    agency, means, way
    how a result is obtained or an end is achieved
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