The meaning of Tetrad and additional information.

Tetrad(n.) The number four; a collection of four things; a quaternion.

Tetrad(n.) A tetravalent or quadrivalent atom or radical; as, carbon is a tetrad.

Tetradic(a.) Of or pertaining to a tetrad; possessing or having the characteristics of a tetrad; as, a carbon is a tetradic element.