(adj) used of a chromosome that is not paired or united with its homologous chromosome during synapsis, Ant. bivalent, multivalent, Example:a univalent chromosome
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. [ 1913 Webster ]