crust
crust \'kr*st\ n [ME, fr. L crusta; akin to OE hru-se earth, Gk kryos icy
c]old 1a: the hardened exterior or surface part of bread 1b: a piece of
this or of bread grown dry or hard 2: the pastry cover of a pie 3: a hard
or brittle external coat or covering : as 3a: a hard surface layer (as of
soil or snow) 3b: the outer part of the earth composed essentially of
crystalline rocks 3c: a deposit built up on the interior surface of a wine
bottle during long aging 3d: an encrusting deposit of dried secretions or
exudate; esp : SCAB slang 4: IMPUDENCE, NERVE - crust vb