n. a cephalopod having two gills; a member of the Dibranchiata.
Syn. -- dibranchiate, dibranchiate mollusk. [ WordNet 1.5 +PJC ]

n. 1. comprising all living cephalopods except the family Nautilidae: the orders Octopoda (octopuses) and Decapoda (squids and cuttlefish).
Syn. -- Dibranchiata, subclass ta, Dibranchia, subclass Dibranchia. [ WordNet 1.5 ]

‖n. pl. [ NL., fr. Gr. di- = di`s- twice + &unr_; gills. ] (Zool.) An order of cephalopods which includes those with two gills, an apparatus for emitting an inky fluid, and either eight or ten cephalic arms bearing suckers or hooks, as the octopi and squids. See Cephalopoda. [ 1913 Webster ]

a. (Zool.) Having two gills. -- n. One of the Dibranchiata. [ 1913 Webster ]