crust /krʌst/ BrE AmE noun [uncountable and countable]
[ Date: 1300-1400 ; Language: Latin ; Origin: crusta 'crust, shell' ]
1 . the hard brown outer surface of bread:
sandwiches with the crusts cut off
2 . the baked outer part of foods such as ↑ pie s or ↑ pizza s :
a thin-crust pizza
3 . a thin hard dry layer on the surface of something:
A hard gray crust had formed on the bottom of the tea kettle.
4 . the hard outer layer of the Earth:
deep within the Earth’s crust
⇨ earn a crust at ↑ earn (1), ⇨ ↑ upper crust