nautilus

noun (plural nautiluses or nautili /-lʌɪ, -liː/)

• 1a cephalopod mollusc with a light external spiral shell and numerous short tentacles around the mouth.

  • Genus Nautilus, the only surviving genus of the subclass Nautiloidea: several species, in particular the pearly nautilus

• 2 (also paper nautilus)another term for argonaut.