An animal belonging to the class Crustacea.

An arthropod of the phylum Crustacea, crustaceans have a hard shell and are usually aquatic. (lobsters, crabs, and shrimp are crustaceans)

Aquatic arthropods including lobsters, crabs, shrimps, and barnacles, characteristically having a segmented body, a hard exoskeleton, and paired, jointed limbs.

A class of arthropod with 10 jointed legs, antennae, and a hard exoskeleton. Crustaceans are primarily aquatic organisms. Examples includes lobsters, crabs, shrimps, and copepods.