/kru stay"sheuhn/ , 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.
adj.
2. belonging or pertaining to the crustaceans.
[ 1825-35; Crustace ( a ) (neut. pl.) hard-shelled ones (see CRUST, -ACEA) + -AN ]