WordNet Dictionary
Webster's 1913 Dictionary\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.
Biology Dictionary- A pair of homologous chromosomes which have joined together (are synapsed) during prophase I and metaphase I of meiosis.
- An atom or radical group which has a valence of two, or which can combine with two (rather than one) different other atoms or molecules.