The Collaborative International Dictionary of English v.0.48:

Gynecocracy \Gyn`e*coc"ra*cy\ (j[i^]n`[-e]*k[o^]k"r[.a]*s[y^]),
   n. [Gr. gynaikokrati`a; gynh`, gynaiko`s, a woman + kratei^n
   to rule: cf. F. gyn['e]cocratie. Cf. Gynocracy.]
   Government by a woman, female power; gyneocracy. --Bailey.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gynecocracy
    n 1: a political system governed by a woman [syn: gynecocracy,
         gynarchy]