'Tooth' is PIE *h-dont- — literally 'the eating one.' Same root as 'dental' and 'dandelion' (lion's tooth).
Each of a set of hard, bony structures in the jaws used for biting and chewing.
From Old English 'tōþ' (tooth), from Proto-Germanic *tanþs, from PIE *h₁dónt- (tooth), itself the present participle of PIE *h₁ed- (to eat), meaning literally 'the eating one' or 'the biter' — a tooth was originally named not as an object but as an agent. This makes 'tooth' one of the oldest deverbal agent nouns in the Indo-European family. The same root *h₁dónt- gave Latin 'dēns' (tooth — in 'dental,' 'dentist,' 'denture,' 'indent,' 'dandelion' from French 'dent de lion,' lion's tooth), Greek 'odoús' (tooth — in 'orthodontics,' 'mastodon' from Greek 'mastos odous,' breast-tooth, referring to nipple-shaped