What does tooth mean?
Tooth is the standard English word for one of the hard structures in the mouth. Teeth perform essential functions: they cut and crush food, help people bite and chew, and contribute to speech and facial appearance. In everyday use, the word often evokes dental care, toothache, cavities, or the familiar phrase of escaping “by the skin of your teeth.” Its broader meaning covers any projecting part shaped like a tooth, including the points of a comb, the edge of a saw, and the raised sections of a gear or wheel. The related verb “tooth” is much less common and can describe the formation of teeth or projections, as well as the engagement of toothed mechanisms. Although “tooth” can refer to a single oral structure, the plural “teeth” is used both generally and when discussing the whole set in the mouth. The word is useful not only anatomically but also in describing the repeated, interlocking shapes that make many tools and machines function.
A hard structure in the mouth used for biting and chewing; also, by extension, a sharp projecting part of a comb, saw, gear, or similar object.
"He went to the dentist because one of his back teeth had become sensitive."
To form teeth or tooth-like projections, or to engage with another toothed part.
"The two gears tooth together as the mechanism turns."
This use is much less common than the noun and is chiefly found in technical or literary contexts.
“Teeth” is the irregular plural of “tooth” and is used when referring to multiple oral structures or to the teeth collectively.
"The child's teeth were being counted during the dental examination."
The word shares an ancient root with dental, dentist, and dentition: the whole family is built around the idea of a tooth.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of tooth
The word descends from Old English tōþ, inherited from Proto-Germanic *tanþą, and related forms appear in other Germanic languages. Its deeper root is generally identified with Proto-Indo-European *dent- “tooth,” also underlying Latin dens, from which dental, dentist, and dentition were borrowed or formed. Latin denticulus, the source of denticle, belongs to the same Latin dental family.
Related word forms
How tooth is actually used
As a countable noun, “tooth” refers to an individual structure, while “teeth” is the irregular plural. The word is standard in British and American English, with specialized uses in dentistry, engineering, and descriptions of combs and saws.
Easily confused with tooth
A tooth is any of the hard structures in the mouth, whereas a tusk is a long, projecting tooth found mainly in certain animals.