Source : Webster's Revised Unabridged Dictionary (1913)

Tetravalent \Te*trav"a*lent\, a. [Tetra- + L. valens, -entis, p.
   pr.] (Chem.)
   Having a valence of four; tetratomic; quadrivalent.

Source : WordNet®

tetravalent
     adj : haveing a valence of four