early 15c., from Old French naval (14c.) and directly from Latin navalis "pertaining to a ship or ships," from navis "ship," from PIE *nau- (2) "boat" (cognates: Sanskrit nauh, accusative navam "ship, boat;" Armenian nav "ship;" Greek naus "ship," nautes "sailor;" Old Irish nau "ship;" Welsh noe "a flat vessel;" Old Norse nor "ship"). An Old English word for "naval" was scipherelic.