tooth

American  

[tooth] / tuθ /

noun

plural

teeth

1. (in most vertebrates) one of the hard bodies or processes usually attached in a row to each jaw, serving for the prehension and mastication of food, as weapons of attack or defense, etc., and in mammals typically composed chiefly of dentin surrounding a sensitive pulp and covered on the crown with enamel.

2. (in invertebrates) any of various similar or analogous processes occurring in the mouth or alimentary canal, or on a shell.

3. any projection resembling or suggesting a tooth.

4. one of the projections of a comb, rake, saw, etc.

5. Machinery.

   1. any of the uniform projections on a gear or rack by which it drives, or is driven by, a gear, rack, or worm.

   2. any of the uniform projections on a sprocket by which it drives or is driven by a chain.

6. Botany.

   1. any small, toothlike marginal lobe.

   2. one of the toothlike divisions of the peristome of mosses.

7. a sharp, distressing, or destructive attribute or agency.

8. taste, relish, or liking.

   Synonyms:

   predilection, partiality, fondness

9. a surface, as on a grinding wheel or sharpening stone, slightly roughened so as to increase friction with another part.

10. a rough surface created on a paper made for charcoal drawing, watercolor, or the like, or on canvas for oil painting.

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verb (used with object)

toothed, toothing

1. to furnish with teeth.

2. to cut teeth upon.

verb (used without object)

toothed, toothing

1. to interlock, as cogwheels.

idioms

1. by the skin of one's teeth, barely.

   He got away by the skin of his teeth.

2. show one's teeth, to become hostile or threatening; exhibit anger.

   Usually friendly, she suddenly began to show her teeth.

3. set / put one's teeth on edge,

   1. to induce an unpleasant sensation.

   2. to repel; irritate.

      The noise of the machines sets my teeth on edge.

4. long in the tooth, old; elderly.

5. cast / throw in someone's teeth, to reproach someone for (an action).

   History will ever throw this blunder in his teeth.

6. to the teeth, entirely; fully.

   armed to the teeth; dressed to the teeth in furs.

7. cut one's teeth on, to do at the beginning of one's education, career, etc., or in one's youth.

   The hunter boasted of having cut his teeth on tigers.

8. in the teeth of,

   1. so as to face or confront; straight into or against.

      in the teeth of the wind.

   2. in defiance of; in opposition to.

      She maintained her stand in the teeth of public opinion.

9. set one's teeth, to become resolute; prepare for difficulty.

   He set his teeth and separated the combatants.

10. put teeth in / into, to establish or increase the effectiveness of.

    to put teeth into the law.

tooth British  

/ tuːθ /

noun

1. any of various bonelike structures set in the jaws of most vertebrates and modified, according to the species, for biting, tearing, or chewing

2. any of various similar structures in invertebrates, occurring in the mouth or alimentary canal

3. anything resembling a tooth in shape, prominence, or function

   the tooth of a comb

4. any of the various small indentations occurring on the margin of a leaf, petal, etc

5. any one of a number of uniform projections on a gear, sprocket, rack, etc, by which drive is transmitted

6. taste or appetite (esp in the phrase sweet tooth )

7. old or ageing: used originally of horses, because their gums recede with age

8. with ferocity and force

   we fought tooth and nail

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verb

1. (tr) to provide with a tooth or teeth

2. (intr) (of two gearwheels) to engage

tooth Scientific  

/ to̅o̅th /

plural

teeth

1. Any of the hard bony structures in the mouth used to grasp and chew food and as weapons of attack and defense. In mammals and many other vertebrates, the teeth are set in sockets in the jaw. In fish and amphibians, they grow in and around the palate.

2. See also dentition

3. A similar structure in certain invertebrate animals.

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tooth Cultural  

1. A hard structure, embedded in the jaws of the mouth, that functions in chewing. The tooth consists of a crown, covered with hard white enamel; a root, which anchors the tooth to the jawbone; and a “neck” between the crown and the root, covered by the gum. Most of the tooth is made up of dentin, which is located directly below the enamel. The soft interior of the tooth, the pulp, contains nerves and blood vessels. Humans have molars for grinding food, incisors for cutting, and canines and bicuspids for tearing.

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tooth More Idioms  

More idioms and phrases containing tooth

• fight tooth and nail
• fine-tooth comb
• long in the tooth
• sweet tooth
• teeth

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Other Word Forms

• toothless
  adjective
• toothlike
  adjective

Etymology

Origin of tooth

before 900; Middle English; Old English tōth; cognate with Dutch tand, German Zahn, Old Norse tǫnn; akin to Gothic tunthus, Latin dēns, Greek odoús (Ionic odṓn ), Sanskrit dánta

Explanation

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.

Example Sentences

Root canal treatment works by removing infected tissue inside the tooth and sealing the area to prevent bacteria and toxins from spreading into surrounding tissues.

From Science Daily • May 16, 2026

When bacteria spread into the tissues surrounding the tooth root, the immune system reacts.

From Science Daily • May 16, 2026

One farmer in Scotland, where the eagles were reintroduced in 1975, said those in Exmoor should fight plans "tooth and nail" or risk losing lambs to the birds.

From BBC • May 13, 2026

In anticipation of Sunday, I’ve been stocking up on all the ingredients I’ll need to make a dessert that’s guaranteed to satisfy my mom’s sweet tooth.

From Salon • May 10, 2026

Renn untied the rowan-bark box that held the stone tooth, and tipped in the river eyes; then she refastened the box, put it back in the pouch, and tied it to her belt.

From "Wolf Brother" by Michelle Paver