1. The outer bark of an oak, Quercus suber, of Mediterranean countries, used for making stoppers for bottles, floats, etc.
2. A cork oak; the tree itself.
3. Something made of cork.
4. A piece of cork, rubber, or the like used as a stopper, as for a bottle.
5. Fish angling: a small float to buoy up a fishing line or to indicate that a fish is biting.
6. An outer tissue of bark produced by and exterior to the phellogen.
7. To provide or to fit with cork or a cork.
8. To blacken with burnt cork.
9. Idiom: to blow or pop one's cork = to lose one's temper; to release one's emotional or physical tension.