nautilus

n (pl ~es) small sea animal that has a spiral-shaped shell, the female's being very thin 鹦鹉螺.

nature, nature study, nature trail, naturism, naturist, naturopath, naturopathic, naturopathically, naturopathy, naught, naughtily, naughtiness, naughty, nausea, nauseate, nauseating, nauseatingly, nauseous, nautical, nautical mile, naval, nave, navel, navel orange, navigability, navigable, navigate, navigation, navigational, navigator, navvy, navy, navy blue (also navy), nay, naysayer, Nazi, Nazism, NB (also nb), NBC, NCO,