CRUST

[noun] - a hard outer covering of somethingThere was a thin crust of dirt around the bath. [C]Pie crust (= the cooked pastry on top of it) should be crisp and golden brown. [U]The crust on a loaf of bread is the outside layer of it.Could you cut the crusts off the sandwiches, please?See picture: BreadA crust is also a small piece of dry bread.All he had in his pocket was an apple and a dry crust.The crust of a planet is its hard outer layer that consists mainly of rock.