Noun | 1. | ![]() Mollusca, phylum Mollusca - gastropods; bivalves; cephalopods; chitons cephalopod, cephalopod mollusk - marine mollusk characterized by well-developed head and eyes and sucker-bearing tentacles family Nautilidae, Nautilidae - spiral-shelled cephalopods Dibranchia, Dibranchiata, subclass Dibranchia, subclass Dibranchiata - comprising all living cephalopods except the family Nautilidae: the orders Octopoda (octopuses) and Decapoda (squids and cuttlefish) class - (biology) a taxonomic group containing one or more orders |