Definition of: crust

(krust) noun
1. A hard, thin coating, usually over something softer.
2. The outer part of bread; a bit of bread, especially if stale and hard.
3. The pastry envelope of a pie or the like.
4. An incrustation, especially from wine, on the interior of bottles.
5. A coating, as of coagulated blood or other solidified exudate of the body.
6. The cold, exterior portion or zone of the earth.
7. The part of a horse's hoof on which the shoe is nailed.
8. A crisp firm surface upon snow.
9. Slang Insolence; impertinence.
—v.t. & v.i. To cover with or acquire a crust. [<L crusta crust]
—crust′al adjective
—crust′ed adjective