nautilus (n.) Look up nautilus at Dictionary.com
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," from nautes "sailor," from naus "ship" (see naval). The cephalopod formerly was thought to use its webbed arms as sails.