[kruh-stey-shuh
n] 
| 1. | any chiefly aquatic arthropod of the class Crustacea, typically having the body covered with a hard shell or crust, including the lobsters, shrimps, crabs, barnacles, and wood lice. |
| 2. | belonging or pertaining to the crustaceans. |
| crus·ta·cean (krŭ-stā'shən) n. Any of various predominantly aquatic arthropods of the class Crustacea, including lobsters, crabs, shrimps, and barnacles, characteristically having a segmented body, a chitinous exoskeleton, and paired, jointed limbs. adj. Of or belonging to the Crustacea. [From New Latin Crūstācea, class name, neuter pl. of crūstāceus, hard-shelled, from Latin crūsta, shell; see kreus- in Indo-European roots.] |
A class of arthropods with shells.
Note: Crabs, lobsters, shrimp, and crayfish are crustaceans.