'Tetrad' definitions:
Definition of 'tetrad'
(from WordNet)
noun
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]
Definition of 'Tetrad'
From: GCIDE
- Tetrad \Tet"rad\, n. [L. tetras, -adis, Gr. ?, ?: cf. F. t['e]trade.]
- 1. The number four; a collection of four things; a quaternion. [1913 Webster]
- 2. (Chem.) A tetravalent or quadrivalent atom or radical; as, carbon is a tetrad. [1913 Webster] Tetradactyl