nautilus

(noun) a submarine that is propelled by nuclear power. Synonyms: nuclear submarine, nuclear-powered submarine.

(noun) cephalopod mollusk of warm seas whose females have delicate papery spiral shells. Synonyms: paper nautilus, Argonaut, Argonauta argo.

(noun) cephalopod of the Indian and Pacific oceans having a spiral shell with pale pearly partitions. Synonyms: chambered nautilus, pearly nautilus.