虫歯
むしば · mushiba · JLPT N3 · noun
pit
🐛🦷 虫歯 = bug + tooth: a tooth the bugs have eaten
虫 (mushi) means bug and 歯 (ha, voiced to ba) means tooth. The word comes from an old belief, found in Japan and Europe, that tiny worms bored the holes in decaying teeth.