tooth

Concise Oxford English Dictionary © 2008 Oxford University Press:
tooth/tuːθ/

▶noun (pl. teeth)

• 1 each of a set of hard, bony enamel-coated structures in the jaws, used for biting and chewing.

• 2 a projecting part, especially a cog on a gearwheel or a point on a saw or comb.

• 3 (teeth) genuine power or effectiveness: the Charter would be fine if it had teeth.

• 4 an appetite or liking for a particular thing.

– phrases
armed to the teeth formidably armed.
fight tooth and nail fight very fiercely.
get (or sink) one's teeth into work energetically and productively on.
in the teeth of

• 1 directly against (the wind).

• 2 in spite of (opposition or difficulty).

– derivatives
toothed adjective,
tooth-like adjective.

– origin OE tōth (pl. tēth), of Gmc origin.