crust

[krʌst]
n
the hard outer part of bread.a piece of bread consisting mainly of this
the baked shell of a pie, tart, etc
any hard or stiff outer covering or surface
a crust of ice
the solid outer shell of the earth, with an average thickness of 30--35 km in continental regions and 5 km beneath the oceans, forming the upper part of the lithosphere and lying immediately above the mantle, from which it is separated by the Mohorovičić discontinuitySee sial See sima
the dry covering of a skin sore or lesion; scab
a layer of acid potassium tartrate deposited by some wine, esp port, on the inside of the bottle
the hard outer layer of such organisms as lichens and crustaceans
impertinence
a living (esp in the phrase earn a crust)
vb
to cover with or acquire a crust
to form or be formed into a crust