The Collaborative International Dictionary of English v.0.48:

Gaea \Gaea\ (j[=e]"[.a]), prop. n. [Gr. Gai^a, Gh^] (Mythol.)
   The goddess of the earth, considered as a personification of
   the earth. According to Hesiod she was the first-born of
   Chaos, and mother of Uranus, Pontus, Cronus and the Titans in
   ancient mythology. [Also spelled Gaia.]

   Syn: Gaia, Ge.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Gaea
    n 1: (Greek mythology) goddess of the earth and mother of Cronus
         and the Titans in ancient mythology [syn: Gaea, Gaia,
         Ge]