'Crustacean' definitions:

Definition of 'crustacean'

(from WordNet)
adjective
Of or belonging to the class Crustacea [syn: crustaceous, crustacean]
noun
Any mainly aquatic arthropod usually having a segmented body and chitinous exoskeleton

Definition of 'Crustacean'

From: GCIDE
  • Crustacean \Crus*ta"cean\ (kr?s-t?"shan; 97), a. (Zool.) Of or pertaining to the Crustacea; crustaceous. -- n. An animal belonging to the class Crustacea. [1913 Webster]