crus ‧ ta ‧ cean /krʌˈsteɪʃ ə n/ BrE AmE noun [countable] technical
[ Date: 1800-1900 ; Language: Modern Latin ; Origin: crustaceus , from Latin crusta ; ⇨ ↑ crust ]
an animal such as a ↑ lobster or a ↑ crab that has a hard outer shell and several pairs of legs, and usually lives in water
—crustacean adjective