The Collaborative International Dictionary of English v.0.48:

chairwoman \chairwoman\ n.
   a female officer who presides at the meetings of a committee,
   meeting, or organization; a female chairperson.

   Syn: president, chairman, chair, chairperson.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

chairwoman
    n 1: the officer who presides at the meetings of an
         organization; "address your remarks to the chairperson"
         [syn: president, chairman, chairwoman, chair,
         chairperson]