Tetradynamian \Tet`ra*dy*na"mi*an\, n. (Bot.) A plant of the order Tetradynamia. Tetradynamian \Tet`ra*dy*na"mi*an\, Tetradynamous \Tet`ra*dyn"a*mous\, a. (Bot.) Belonging to the order Tetradynamia; having six stamens, four of which are uniformly longer than the others.