tetrad : Dictionary / Wörterbuch (BEOLINGUS, TU Chemnitz)

English Dictionary: tetrad	by the DICT Development Group
2 results for tetrad
From WordNet (r) 3.0 (2006) [wn]:
tetrad n the cardinal number that is the sum of three and one [syn: four, 4, IV, tetrad, quatern, quaternion, quaternary, quaternity, quartet, quadruplet, foursome, Little Joe]
From Webster's Revised Unabridged Dictionary (1913) [web1913]:
Tetrad \Tet"rad\, n. [L. tetras, -adis, Gr. [?], [?]: cf. F. t[82]trade.] 1. The number four; a collection of four things; a quaternion. 2. (Chem.) A tetravalent or quadrivalent atom or radical; as, carbon is a tetrad.