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]

Moby Thesaurus II by Grady Ward, 1.0:

95 Moby Thesaurus words for "Gaea":
   Agdistis, Amor, Aphrodite, Apollo, Apollon, Ares, Artemis, Ate,
   Athena, Bacchus, Ceres, Cora, Cronus, Cupid, Cybele, Demeter,
   Despoina, Diana, Dionysos, Dionysus, Dis, Earth, Eros, Flora, Frey,
   Gaia, Ge, Great Mother, Hades, Helios, Hephaestus, Hera, Here,
   Hermes, Hestia, Hymen, Hyperion, Jove, Juno, Jupiter,
   Jupiter Fidius, Jupiter Fulgur, Jupiter Optimus Maximus,
   Jupiter Pluvius, Jupiter Tonans, Kore, Kronos, Magna Mater, Mars,
   Mercury, Minerva, Mithras, Momus, Neptune, Nike, Olympians,
   Olympic gods, Ops, Orcus, Persephassa, Persephone, Phoebus,
   Phoebus Apollo, Pluto, Pomona, Poseidon, Proserpina, Proserpine,
   Rhea, Saturn, Tellus, Terra, Triptolemos, Triptolemus, Venus,
   Vesta, Vulcan, Zeus, biosphere, corn god, fertility god,
   forest god, geography, geosphere, globe, mother earth, terra,
   terrestrial globe, the blue planet, this pendent world, vale,
   vale of tears, vegetation spirit, whole wide world, world