epicene

adj. 1 of, for, denoting, or used by both sexes. 2 having characteristics of both sexes or of neither sex. n. Epicene person. [greek koinos common]

a. & n. Common to both sexes; -- a term applied, in grammar, to such nouns as have but one form of gender, either the masculine or feminine, to indicate animals of both sexes; as boy^s, bos, for the ox and cow; sometimes applied to eunuchs and hermaphrodites.