crust

noun

• 1the tough outer part of a loaf of bread:a sandwich with the crusts cut off [mass noun]:I tore off several pieces of crust from the loaf
• a hard, dry scrap of bread:a kindly old woman might give her a crust

• 2a hardened layer, coating, or deposit on the surface of something soft:a crust of snow
• a layer of pastry covering a pie.
• the outermost layer of rock of which a planet consists, especially the part of the earth above the mantle:the earth’s crust
• a deposit of tartrates and other substances formed in wine aged in the bottle, especially port.

• 3British informal a living or livelihood:I’ve been earning a crust wherever I can

verb

• form into a hard outer layer:the blisters eventually crust over
• [with object] cover with a hard outer layer:the burns crusted his cheek