Source : Webster's Revised Unabridged Dictionary (1913)

Univalent \U*niv"a*lent\, a. [Uni- + L. valens, -entis, p. pr.
   See {Valence}.] (Chem.)
   Having a valence of one; capable of combining with, or of
   being substituted for, one atom of hydrogen; monovalent; --
   said of certain atoms and radicals.

Source : WordNet®

univalent
     adj 1: used of a chromosome that is not paired or united with its
            homologous chromosome during synapsis; "a univalent
            chromosome" [ant: {bivalent}, {multivalent}]
     2: having a valence of 1 [syn: {monovalent}] [ant: {polyvalent}]