Of or pertaining to a triad; constituting or consisting of a triad or trinity.In chem., trivalent; triatomic.In ancient prosody:Comprising three different rhythms or meters: as, the triadic epiploce.Consisting of pericopes, or groups of systems, each of which contains three unlike systems: as, a triadic poem.In the Gr. Ch., addressed to or in honor of the Trinity: as, a triadic canon.n. A sum of products of three vectors.