crustacean /kɹʌsˈteɪʃən/noun 2adjective 1forms 3 noun2 •Any arthropod of the subphylum Crustacea, including lobsters, crabs, shrimp, barnacles and woodlice. •Any arthropod of the clade Pancrustacea, which includes hexapods in addition to traditional crustaceans. adjective1 •Of, relating to, or characteristic of the subphylum Crustacea.In cooperation with the Bureau of Fisheries he made several motion pictures of crustacean life. — 1940 formscrustaceans · more crustacean · most crustacean