Argonaut n.

name of the ship in which Jason and his 54 heroic companions sought the Fleece in Colchis on the Euxine Sea, in Greek, literally "The Swift," from argos "swift" (adj.), an epithet, literally "shining, bright" (from PIE root *arg- "to shine; white"), "because all swift motion causes a kind of glancing or flickering light" [Liddell & Scott]. Related: Argean.

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."