crust

(noun): A more solid, dense or hard layer on a surface or boundary.
(noun): The external, hardened layer of certain foodstuffs, including most types of bread, fried meat, etc.
(noun): An outer layer composed of pastry
(noun): The bread-like base of a pizza.
(noun): The outermost layer of the lithosphere of the Earth.
(noun): The shell of crabs, lobsters, etc.
(noun): Nerve, gall.
(noun): A living.
(verb): To cover with a crust.
(verb): To form a crust.
(noun): A subgenre of punk rock, derived from hardcore punk with extreme metal elements, often with pessimistic lyrics about political and social ills.