The Collaborative International Dictionary of English v.0.48:
Dibranchiate \Di*bran"chi*ate\, a. (Zool.) Having two gills. -- n. One of the Dibranchiata. [1913 Webster]WordNet (r) 3.0 (2006):
dibranchiate n 1: cephalopods having two gills [syn: dibranchiate, dibranchiate mollusk, dibranch]