crust

The definition of crust is the hard, outer part of a loaf of bread, or a layer of pastry covering a pie, or a hardened layer on something.

(noun)

The brown outer part of white bread that you may have to cut off your child's sandwich is an example of crust.
A tiny old piece of the end of a loaf of bread that you might throw to the ducks is an example of a crust of bread.
A layer of dough on the bottom and top of an apple pie is an example of a crust.
A hard film on top of soft pudding is an example of crust.

Crust is defined as forming a hard outer layer.

(verb)

When the ice freezes over a lake, this is an example of when it crusts.

See crust in Webster's New World College Dictionary

noun

1. the hard, crisp outer part of bread
2. a piece of this
3. any dry, hard piece of bread
the pastry shell of a pie
any hard surface layer, as of snow or soil
a hard deposit formed by wine on the inside surface of a bottle
Slang audacity; insolence; gall
Geol. the solid, rocky outer portion or shell of the earth; lithosphere
Med. a dry, hard outer layer of blood, pus, or other bodily secretion

Origin: ME cruste < OFr or L: OFr crouste < L crusta: for IE base see crude

transitive verb, intransitive verb

See crust in American Heritage Dictionary 4

crust

noun

a. The hard outer portion or surface area of bread.
b. A piece of bread consisting mostly of the hard outer portion.
c. A piece of bread that has become hard and dry.
A pastry shell, as of a pie or tart.
A hard crisp covering or surface: snow with a firm crust.
A hard deposit formed on the interior of a wine bottle as the wine matures.
Geology
a. The exterior portion of the earth that lies above the Mohorovičić discontinuity.
b. The outermost solid layer of a planet or moon.
The hard outer covering or integument of certain plants and animals, such as lichens and crustaceans.
Pathology An outer layer or coating formed by the drying of a bodily exudate such as pus or blood; a scab.
Informal Insolence; audacity; gall.