/nawt"l euhs, not"-/ , n. , pl. nautiluses, nautili /nawt"l uy', not"-/ for 1, 2.
1. Also called chambered nautilus, pearly nautilus . any cephalopod of the genus Nautilus, having a spiral, chambered shell with pearly septa.
2. See paper nautilus .
3. ( cap. ) the first nuclear-powered submarine launched by the U.S. Navy.
[ 1595-1605; nautílos paper nautilus, lit., sailor, deriv. of naûs ship; the webbed dorsal arms of the paper nautilus were thought to have been used as sails ]