nautical adj.

suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).

nāu-, Proto-Indo-European root meaning "boat."

It forms all or part of: aeronautics; aquanaut; Argonaut; astronaut; cosmonaut; nacelle; naval; nave (n.1) "main part of a church;" navicular; navigate; navigation; navy; naufragous; nausea; nautical; nautilus; noise.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit nauh, accusative navam "ship, boat;" Armenian nav "ship;" Greek naus "ship," nautes "sailor;" Latin navis "ship;" Old Irish nau "ship," Welsh noe "a flat vessel;" Old Norse nor "ship."

1824, "art of aerial navigation by means of a balloon," from aeronautic (1784), from French aéronautique, from aéro- (see aero-) + nautique "of ships," from Latin nauticus, from Greek nautikos "pertaining to sailing" (see nautical). Also see -ics. Aeronaut "balloonist" is from 1784, from French aéronaute.