Crust

1. The shell of crabs, lobsters, etc.
2. To cover with a crust; to cover or line with an incrustation; to incrust.
3. The cover or case of a pie, in distinction from the soft contents.
4. The hard exterior or surface of bread, in distinction from the soft part or crumb; or a piece of bread grown dry or hard.
5. A hard mass, made up of dried secretions blood, or pus, occurring upon the surface of the body.
6. To gather or contract into a hard crust; to become incrusted.
7. An incrustation on the interior of wine bottles, the result of the ripening of the wine; a deposit of tartar, etc. See Beeswing.
8. The exterior portion of the earth, formerly universally supposed to inclose a molten interior.
9. The hard external coat or covering of anything; the hard exterior surface or outer shell; an incrustation; as, a crust of snow.
10. The dough, or mass of doughy paste, cooked with a potpie; -- also called dumpling.