[New Latin, from Nauplius, former genus of crustacean (later discovered to be a larval stage of other genera), from Latin nauplius, paper nautilus, from Greek nauplios, nautilus (probably the pearly nautilus of the Indian Ocean) : naus, nau-, ship; see nāu- in the Appendix of Indo-European roots + plein, to sail, float, swim (the animal being so called because it was thought to sail in its shell like a ship and use its arms as oars); see pleu- in the Appendix of Indo-European roots.]