Source : Webster's Revised Unabridged Dictionary (1913)

Quadrivalent \Quad*riv"a*lent\, a. [Quadri- + L. valens, -entis,
   p. pr. See {Valence}.] (Chem.)
   Having a valence of four; capable of combining with, being
   replaced by, or compared with, four monad atoms; tetravalent;
   -- said of certain atoms and radicals; thus, carbon and
   silicon are quadrivalent elements.