The number four; a collection of four things; a quaternion. A tetravalent or quadrivalent atom or radical; as, carbon is a tetrad.
n.four, IV, quatern, quaternion, quaternary, quaternity, quartet, quadruplet, foursome, Little Joe, digit generic term, figure generic term
Vogais: ea
Consoantes: ttrd
tetard, tetradite, trad, tetrode, trade, tread, triad, troad, teetered, teratoid.