Webster's Revised Unabridged Dictionary · 1913

Crust

Crust (kr?st) , noun

[Latin crusta: compare Old French crouste, French croûte; prob. akin to Greek {not transcribed} ice, English crystal, from the same root as English crude, raw. See Raw, and compare Custard.]

1.
The hard external coat or covering of anything; the hard exterior surface or outer shell; an incrustation; as, a crust of snow.
I have known the statute of an emperor quite hid under a crust of dross. — Addison
Below this icy crust of conformity, the waters of infidelity lay dark and deep as ever. — Prescott
2.
(a) (Cookery) The hard exterior or surface of bread, in distinction from the soft part or crumb; or a piece of bread grown dry or hard.
(b)
(Cookery) The cover or case of a pie, in distinction from the soft contents.
(c)
(Cookery) The dough, or mass of doughy paste, cooked with a potpie; -- also called dumpling.
Th' impenetrable crust thy teeth defies. — Dryden
He that keeps nor crust nor crumb. — Shakespeare
They... made the crust for the venison pasty. — Macaulay
3.
(Geology) The exterior portion of the earth, formerly universally supposed to inclose a molten interior.
4.
(Zoology) The shell of crabs, lobsters, etc.
5.
(Medicine) A hard mass, made up of dried secretions blood, or pus, occurring upon the surface of the body.
6.
An incrustation on the interior of wine bottles, the result of the ripening of the wine; a deposit of tartar, etc. See Beeswing.

Crust , transitive verb

[Compare Old French crouster, Latin crustare. See Crust, n. ]

To cover with a crust; to cover or line with an incrustation; to incrust.
The whole body is crusted over with ice. — Boyle
And now their legs, and breast, and bodies stood Crusted with bark. — Addison
Very foul and crusted bottles. — Swift
Their minds are crusted over, like diamonds in the rock. — Felton

Crust , intransitive verb

To gather or contract into a hard crust; to become incrusted.
The place that was burnt... crusted and healed. — Temple