1.the thin, usually hard or crisp outer part of a loaf or slice of bread
2.a piece of bread that is mostly crust or is stale and dry
3.the pastry that wholly or partly encases a pie or tart
4.a crisp, hard, or thick outer layer or coating that develops on something
5.the thin outermost layer of Earth, approximately one percent of Earth's volume, that varies in thickness and has a different composition from the interior.
6.a dry hardened outer layer of blood, pus, or other bodily secretion that forms over a cut or sore
7.a thin layer of potassium tartrate that forms on the inside of some wine and port bottles as the contents mature
8.the hard outermost body covering in some living organisms, such as lichens and crustaceans
9.a layer of cooked pastry that forms the outer part of a pie. The inner part is called the filling.
10.the thick outer surface of the Earth or another planet
11.a hard layer of a substance covering a softer substance or a liquid