—n. any arthropod of the class Crustacea, having a hard shell and usu. aquatic, e.g. the crab, lobster, and shrimp.
—adj. of or relating to crustaceans.
Derivatives:
crustaceology n. crustaceous adj.
Etymology: mod.L crustaceus f. crusta: see CRUST
Useful english dictionary. 2012.