chambered nautilus

chambered nautilus (plural chambered nautiluses or chambered nautili)

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.
   • 1956, Arthur C. Clarke, The City and the Stars, page 44:

     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.

2. A nautilus, Nautilus pompilius.

• nautilus