dibranchiata

from The Century Dictionary.

• An order of acetabuliferous cephalopods, containing the decapod and octopod Cephalopoda.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) 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.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun comprising all living cephalopods except the family Nautilidae: the orders Octopoda (octopuses) and Decapoda (squids and cuttlefish)