Tetrad

tefrad, n. The number 4; a collection of 4 things. [Gr. tetras, tetrados, fr. tettares, Attic form of te ares = E.four, q. v.] — Tet'rachord, -ra- D k6rd, n. (Anc. Mus.) A series of 4 sounds, of which the extremes, or first and last, constituted a fourth. [Gr. tetrachord on; chorde = E. chord.}—Tefragon, n. Geom.) A plane figure, having 4 angles; a quadrangle. (Astrol.) An / // aspect of 2 planets with regard to / [__ 7 the earth, when they are distant Tetragons. from'eacn other 9u -ical, a. Consisting of, or having, 4 syllables.