This is the 3395th most frequent Japanese word.
歯
Tooth.
Here, "歯" (teeth) symbolizes a responsibility or common advice related to health and hygiene.
歯を大切にすることが大事です。
It is important to take care of your teeth.
In this sentence, "歯" (teeth) is used to refer to the actual physical teeth in someone's mouth.
彼の歯はとても白い。
His teeth are very white.
In this instance, "歯" metaphorically refers to the lead of a pencil, showing its use in a broader context.