tooth; teeth
tooth (of a comb, saw, etc.); cog
support (of a geta)
「歯」 has other readings with different meanings.
(one's) age
tooth
毎晩寝る前に歯を磨くよ。
I brush my teeth every night before bed.
櫛の歯が一本折れた。
One tooth of the comb broke off.
下駄の歯がすり減ってしまった。
The supports of my geta have worn down.