tooth

tooth — noun

1. a white or off-white part fixed in a row inside your mouth, made of a hard, bone

1.nounA1
Definition

a white or off-white part fixed in a row inside your mouth, made of a hard, bone-like material, used to bite and break food into small pieces before you swallow it.

Example

The dentist told Trang to brush her teeth at least twice every day.

collocation: brush teeth

Valentina's baby cried all night because a new tooth was pushing through her gum.

infant tooth growth

Common collocations
  • brush / clean one's teeth
  • lose a tooth
  • baby / milk / permanent / wisdom tooth
  • tooth decay / cavity
  • front / back / upper / lower teeth
  • bare / show one's teeth
  • grit one's teeth
  • cut a tooth (for babies)

Usage Note

Teeth are counted individually — you say 'I have a loose tooth' (singular) or 'I brush my teeth' (plural). The first set of teeth in children are called baby teeth or milk teeth; these fall out and are replaced by permanent teeth or adult teeth. Common dental verbs include 'brush', 'floss', 'fill', 'extract', and 'pull'.

Common Mistakes

I have a tooth decay.
I have tooth decay.
'tooth decay' is an uncountable noun; do not use 'a'.
My teeth is hurting.
My teeth are hurting.
'teeth' is the plural form and takes a plural verb.
I need to go to dentist for my tooth.
I need to go to the dentist for my tooth.
use the definite article with 'dentist'.

2. one of a set of small, pointed pieces that stick outward from the surface of cer

2.nounB1
Definition

one of a set of small, pointed pieces that stick outward from the surface of certain tools and are designed to help cut, grip, or hold material — found on items like saws, combs, gears, and zippers.

Example

The saw's teeth were so dull that Tuan could not cut through the wooden board.

Ryan ran a comb through his wet hair, and one of the teeth snapped off.

Common collocations
  • teeth of a comb / saw / gear / zipper / rake
  • broken / bent / dull / sharp teeth
  • fine-toothed comb
  • sawtooth / gear tooth
Synonyms
  • cog

    specifically one tooth on a gear wheel

  • tine

    a prong of a fork or rake, similar but not interchangeable

  • prong

    a pointed projection, usually on a fork or electrical plug

Grammar Patterns

the teeth of a [tool]

[tool] + tooth / teeth

Usage Note

This sense is most common in compound nouns and fixed expressions: 'fine-toothed comb', 'sawtooth', 'gear tooth', and 'toothed wheel'. The singular form (e.g., 'one tooth on the gear is broken') is used when referring to a single projection.

Common Mistakes

The comb's tooths are broken.
The comb's teeth are broken.
the plural is always 'teeth', never 'tooths'.
I need a fine-tooth comb.
I need a fine-toothed comb.
the adjective form is 'fine-toothed'.

3. the ability of a law, rule, committee, or other authority to be taken seriously

3.nounB2
Definition

the ability of a law, rule, committee, or other authority to be taken seriously and to force people to obey or comply, usually because it has real punishment or enforcement power.

Example

The new regulations give the environmental agency real teeth to punish polluters.

pattern: give [something] teeth

Without an inspection system, the safety rules have no teeth and companies ignore them.

Common collocations
  • give (something) teeth
  • have / lack teeth
  • real / actual teeth
  • a law / regulation / agency with teeth
Synonyms
  • enforcement power

    more explicit, used in formal/legal contexts

  • authority

    broader in meaning; includes legal right, not just the power to enforce

  • bite

    informal synonym, e.g., 'the new rules have bite'

Grammar Patterns

give [noun] teeth

[noun] has / lacks teeth

[noun] with teeth

Usage Note

Almost always used in specific phrases such as 'give teeth to', 'have teeth', 'lack teeth', or 'with teeth'. The subject is usually an abstract entity — a law, regulation, policy, committee, sanction, or agreement. Never used in the singular ('a tooth') with this figurative meaning. This sense is most common in news, political, and legal writing.

Common Mistakes

The law has a tooth now.
The law has teeth now.
always use the plural 'teeth' for this figurative meaning.
The tooth of the law is weak.
The law lacks teeth.
use the standard fixed expression rather than an unusual singular form.
Idioms

fight tooth and nail

idiom

to use every possible effort to achieve or defend something, especially against strong opposition.

The local residents fought tooth and nail to stop the factory from being built near the school.

Sivan fought tooth and nail for her right to study at the university despite the new rules.

have a sweet tooth

idiom

to like eating sweet foods, especially candy, chocolate, and desserts.

Tyler has a real sweet tooth and always orders chocolate cake for dessert.

If you have a sweet tooth, you will love the mango sticky rice at that Thai restaurant.

cut one's teeth on

idiom

to gain your first experience or training in a particular area or skill by doing something specific.

The young chef cut his teeth on simple dishes at a small restaurant before opening his own place.

Imran cut his teeth on programming video games as a teenager, which led to a career in software.

get one's teeth into

idiom

to start doing something with a lot of energy and enthusiasm, especially something that is challenging or interesting enough to hold your attention.

The research project was complicated, and Ezra was excited to finally get his teeth into it.

After two weeks of training, the new team finally got their teeth into the real work.

long in the tooth

idiom

old or too old; past one's prime (informal, sometimes humorous).

At forty-five, some people think an athlete is too long in the tooth to compete at the top level.

The company's computers are getting a bit long in the tooth and need to be replaced.

lie through one's teeth

idiom

to say something that is completely and obviously untrue.

The salesman lied through his teeth when he claimed the old car had never been in an accident.

The manager was lying through her teeth about having completed the report, and everyone knew it.

by the skin of one's teeth

idiom

by the smallest possible margin; very narrowly, especially when managing to avoid failure or disaster.

Ezra passed the final exam by the skin of his teeth, scoring just above the minimum grade.

The rescue team arrived by the skin of their teeth as the building began to collapse.

grit one's teeth

idiom

to press your teeth together tightly; to decide to continue doing something difficult or unpleasant with determination.

Amira gritted her teeth and kept running despite the sharp pain in her knee.

The team gritted their teeth and worked through the weekend to meet the deadline.

armed to the teeth

idiom

Carrying many weapons.

The soldiers were armed to the teeth for the dangerous mission.

Why are those guards armed to the teeth?

bare your teeth

idiom

To show your teeth as a sign of anger or threat.

The wolf bared its teeth and growled at the hikers.

When cornered, the cat bared its teeth and hissed.

by the skin of your teeth

idiom

Only just managing to do something; very narrowly.

We caught the train by the skin of our teeth.

She passed the exam by the skin of her teeth.

cut your teeth on something

idiom

To gain your first experience of a particular type of work by doing it.

He cut his teeth on small indie films before directing blockbusters.

Many journalists cut their teeth on local newspapers.

cut a tooth

idiom

To have a new tooth start growing through the gum.

The baby is crying because she is cutting a tooth.

My son cut his first tooth at six months old.

an eye for an eye (and a tooth for a tooth)

idiom

The idea that a person who has harmed someone should be punished by having the same thing done to them.

Some people believe in an eye for an eye as justice.

The principle of an eye for an eye is ancient.

get the bit between your teeth

idiom

To become very determined to do something and unlikely to stop until you finish.

Once she gets the bit between her teeth, nothing stops her.

He got the bit between his teeth and finished the project in a week.

get your teeth into something

idiom

To start doing something with a lot of energy and interest, especially something challenging.

I need a new project I can really get my teeth into.

She got her teeth into the research and made great progress.

gnash your teeth

idiom

To press your teeth together in anger or frustration; to be very angry about something you cannot change.

He gnashed his teeth when he heard the bad news.

Fans gnashed their teeth after the team lost the final.

grit your teeth

idiom

To press your teeth together tightly, often to deal with pain or a difficult situation.

She gritted her teeth and lifted the heavy box.

We gritted our teeth and finished the race.

have teeth

idiom

To have real power and be able to be effective.

The new law has teeth and will punish violators.

Does this committee have teeth to enforce rules?

Hell’s teeth

idiom

Used to express anger or surprise.

Hell's teeth, I forgot my keys again!

Hell's teeth, that was a close call.

in the teeth of something

idiom

Despite facing problems, opposition, or difficulty.

They continued the project in the teeth of strong criticism.

The ship sailed on in the teeth of the storm.

kick somebody in the teeth

idiom

To treat someone badly or refuse to help them when they need it.

After all his hard work, the company kicked him in the teeth.

She felt kicked in the teeth when her friend didn't support her.

a kick in the teeth

idiom

An event that causes great disappointment or emotional hurt.

Losing the job was a real kick in the teeth for him.

The rejection felt like a kick in the teeth.

lie through your teeth

idiom

To say something that is completely untrue.

The suspect lied through his teeth during the interview.

She was lying through her teeth about her qualifications.

like pulling teeth

idiom

Used to say that getting someone to do something is very difficult.

Getting him to talk about his feelings is like pulling teeth.

It's like pulling teeth to get the kids to do their homework.

red in tooth and claw

idiom

Involving fierce and violent competition or opposition.

Nature is red in tooth and claw, with predators hunting prey.

The business world is red in tooth and claw.

set somebody’s teeth on edge

idiom

To make someone feel annoyed or uncomfortable, often because of a sound or behavior.

The sound of nails on a chalkboard sets my teeth on edge.

His constant complaining sets her teeth on edge.

Word family

Synonym discussion

Sense: noun/1

All of these words describe hard, pointed structures in or near the mouth, but they differ in scope and specific meaning. 'Tooth' is the general term for the white, bone-like parts in the human mouth used for biting and chewing. 'Fang' refers specifically to the long, sharp teeth of animals such as snakes, wolves, and spiders, used for biting or injecting venom — humans do not have fangs. 'Tusk' describes the extremely long, protruding teeth found on animals like elephants, walruses, and wild boars, used for self-defense or digging. 'Molar' is one of the broad, flat teeth at the back of the human mouth, designed for grinding food into smaller pieces. For example: 'The dentist said my back molars have small cavities.' 'A wolf bared its fangs at the hikers.' 'The elephant used its tusks to lift the fallen branch out of the path.'

fangtuskmolar

Common collocations

Phrases

Etymology

Proto-Indo-EuropeanProto-GermanicOld EnglishEnglish

From Old English 'tōþ' (tooth), tracing back through Proto-Germanic '*tanþs' to the Proto-Indo-European root '*h₃dónts', meaning 'tooth'. This ancient root also gave rise to the Greek word 'odṓn' (seen in 'orthodontist') and the Latin word 'dēns' (seen in 'dentist', 'dental', and 'dentifrice'). The word 'tooth' has remained remarkably stable in form for well over a thousand years of English.