nautilus (n.)

marine cephalopod, c. 1600, from Latin nautilus, in Pliny a kind of marine snail (including also squid, cuttlefish, polyps, etc.), from Greek nautilos "paper nautilus," literally "sailor," a poetic form of nautēs "sailor," from naus "ship" (from PIE root *nau- "boat"). From Aristotle into the 19c., the nautilus was believed to use its webbed arms to sail along the surface of the sea, hence the name.

For thus to man the voice of nature spake,
Go, from the creatures thy instruction take,
Learn of the little Nautilus to sail,
Spread the thin oar, and catch the driving gale
[Pope ]

Others are reading

Definitions of nautilus from WordNet

nautilus (n.)
a submarine that is propelled by nuclear power;
Synonyms: nuclear submarine / nuclear-powered submarine
nautilus (n.)
cephalopod mollusk of warm seas whose females have delicate papery spiral shells;
Synonyms: paper nautilus / Argonaut / Argonauta argo
nautilus (n.)
cephalopod of the Indian and Pacific oceans having a spiral shell with pale pearly partitions;
Synonyms: chambered nautilus / pearly nautilus