The Collaborative International Dictionary of English v.0.48:
Nautilidae \Nautilidae\ prop. n. A natural family of spiral-shelled cephalopods. Syn: family Nautilidae. [WordNet 1.5]WordNet (r) 3.0 (2006):
Nautilidae n 1: spiral-shelled cephalopods [syn: Nautilidae, family Nautilidae]