nautilus

noun

Etymology: From Latin nautilus, from Ancient Greek ναυτίλος (nautílos, “paper nautilus, sailor”).

1. 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.

   “He was still prepared to go on collecting all that life could offer, like a chambered nautilus patiently adding new cells to its slowly expanding spiral.”

   “Nautilidan cephalopods, represented today by the six living species of nautilus are thought to have diverged from other nautiloids in the Devonian period.”

2. A kind of diving bell that sinks or rises by means of compressed air.
3. A paper nautilus (actually an octopus).