English UsageGrammar guide
Plural of Tooth
The plural of “tooth” is “teeth.” It is an irregular plural, so ordinary countable uses do not form the plural by adding -s.
The plural of “tooth” is “teeth,” not “tooths.”
Key details
Confusion Familyirregular plural
Rule Familyplural and countability
Termstooth, teeth
Variant ScopeThe standard plural of the count noun tooth is teeth.
Further guidance
Core difference
“Tooth” is singular; “teeth” is its irregular plural.
Fast Test
Use “one tooth” but “two teeth,” “several teeth,” and plural verb agreement where required.
Usage Boundary
Do not form the ordinary plural as “tooths.” Specialized compounds may contain “tooth” attributively, but that does not change the noun’s plural.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- tooth — Cambridge Dictionary (opens in a new tab)Cambridge University Press · Direct dictionary evidence that the plural of tooth is teeth.