Source : Webster's Revised Unabridged Dictionary (1913)

Bivalent \Biv"a*lent\, a. [L. bis twice + valens, p. pr. See
   {Valence}.] (Chem.)
   Equivalent in combining or displacing power to two atoms of
   hydrogen; dyad.

Source : WordNet®

bivalent
     adj 1: having a valence of two or having two valences [syn: {divalent}]
     2: used of homologous chromosomes associated in pairs in
        synapsis [syn: {double}] [ant: {multivalent}, {univalent}]