What is the meaning of Nautilus?

A marine mollusc, of the family Nautilidae native to the Pacific Ocean and Indian Ocean, which has tentacles and a spiral shell with a series of air-filled chambers, of which Nautilus is the type genus.

A kind of diving bell that sinks or rises by means of compressed air.

paper nautilus, argonaut (genus Argonauta)

Alternative form of nautil

Source: wiktionary.org