The Collaborative International Dictionary of English v.0.48:
Belemnoidea \Belemnoidea\ n. an order of extinct dibranchiate cephalopods related to the surviving spirulas. Syn: order Belemnoidea. [WordNet 1.5]WordNet (r) 3.0 (2006):
Belemnoidea n 1: order of extinct dibranchiate cephalopods related to the surviving spirulas [syn: Belemnoidea, order Belemnoidea]