The Collaborative International Dictionary of English v.0.48:

Gynecology \Gyn`e*col"o*gy\ (j[i^]n`[-e]*k[o^]l"[-o]*j[y^] or
   g[imac]`n[-e]-), n. [Gr. gynh`, gynaiko`s, a woman + -logy.]
   The science which treats of the structure and diseases of
   women. -- Gyn`e*col"o*gist.
   [1913 Webster]

WordNet (r) 3.0 (2006):

gynecology
    n 1: the branch of medicine that deals with the diseases and
         hygiene of women [syn: gynecology, gynaecology]