The Collaborative International Dictionary of English v.0.48:

Epicene \Ep"i*cene\, a. & n. [L. epicoenus, Gr. ?; fr. 'epi` + ?
   common; cf. F. ['e]pic[`e]ne.]
   1. 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.
      [1913 Webster]

   2. Fig.: Sexless; neither one thing nor the other.
      [1913 Webster]

            The literary prigs epicene.           --Prof.
                                                  Wilson.
      [1913 Webster]

            He represented an epicene species, neither churchman
            nor layman.                           --J. A.
                                                  Symonds.
      [1913 Webster]

WordNet (r) 3.0 (2006):

epicene
    adj 1: having an ambiguous sexual identity [syn: bisexual,
           epicene]
    2: having unsuitable feminine qualities [syn: effeminate,
       emasculate, epicene, cissy, sissified, sissyish,
       sissy]
    n 1: one having both male and female sexual characteristics and
         organs; at birth an unambiguous assignment of male or
         female cannot be made [syn: hermaphrodite, intersex,
         gynandromorph, androgyne, epicene, epicene person]