crust

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The hard outer portion or surface area of bread.
2. n. A piece of bread consisting mostly of the hard outer portion.
3. n. A piece of bread that has become hard and dry.
4. n. A pastry shell, as of a pie or tart.
5. n. A hard crisp covering or surface: snow with a firm crust.
6. n. A hard deposit formed on the interior of a wine bottle as the wine matures.
7. n. Geology The exterior portion of the earth that lies above the Mohorovičić discontinuity.
8. n. Geology The outermost solid layer of a planet or moon.
9. n. The hard outer covering or integument of certain plants and animals, such as lichens and crustaceans.
10. n. Pathology An outer layer or coating formed by the drying of a bodily exudate such as pus or blood; a scab.
11. n. Informal Insolence; audacity; gall.
12. v. To cover with a crust.
13. v. To form into a crust.
14. v. To become covered with a crust.
15. v. To harden into a crust.

Century Dictionary and Cyclopedia

1. n. A hard external portion, of comparative thinness, forming a sort of coating over the softer interior part; any hard outer coat or coating: as, the crust of frozen snow; the crust of a loaf of bread; a thin crust of politeness.
2. n. Specifically In geology: The exterior portion of the earth; that part of the earth which is accessible to examination.
3. n. The solid portion of the earth, as opposed to its fused interior, many geologists and physicists believing that the interior of the earth must be in a more or less fluid condition.
4. n. Matter collected or concreted into a solid body; an incrustation; specifically, a deposit from wine, as it ripens, collected on the interior of bottles, etc., and consisting of tartar and coloring matter.
5. n. A piece of an outer coating or incrustation; specifically, an external or a dried and hard piece of bread.
6. n. In zoology, a shell; a test; the chitinous or other hard covering of various animals, as crustaceans and insects.
7. n. In anatomy and physiology, a coat or covering harder or denser than that which is covered; a pellicle; a crusta: as, the buffy coat or crust of inflammatory blood; the crust of a tooth.
8. n. The part of the hoof of a horse to which the shoe is fastened.
9. To cover with a crust or hard exterior portion or coating; overspread with anything resembling a crust; incrust.
10. To coat or line with concretions. See crust, n., 3.
11. To thicken or contract into a hard covering; concrete or freeze, as superficial matter.
12. To crust-hunt.

Wiktionary

1. n. A more solid, dense or hard layer on a surface or boundary.
2. n. The external layer of most types of bread.
3. n. Outer layer composed of pastry
4. n. Bread foundation of pizza
5. n. geology The outermost layer of the lithosphere of the Earth.
6. n. uncountable Nerve, gall.
7. n. crust punk (a subgenre of punk music)
8. v. transitive To cover with a crust.
9. v. intransitive To form a crust.

GNU Webster's 1913

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

WordNet 3.0

1. n. the trait of being rude and impertinent; inclined to take liberties
2. v. form a crust or form into a crust
3. n. the outer layer of the Earth
4. n. a hard outer layer that covers something