the hardened exterior of bread
a piece of this or of bread grown dry or hard
the pastry cover of a pie
a hard or brittle surface layer
a deposit built up on the inside of a wine bottle
a hard or brittle surface layer, e.g. of soil or snow
the outer rocky layer of the earth
a hard deposit on the skin; esp a scab
a deposit built up on the inside of a wine bottle during long ageing
a superficial hardness or reserve of manner
crustal adj
[Middle English, from Latin crusta rind, shell, crust]