The Collaborative International Dictionary of English v.0.48:

Mythology \My*thol"o*gy\, n.; pl. Mythologies. [F. mythologie,
   L. mythologia, Gr. myqologi`a; my^qos, fable, myth + lo`gos
   speech, discourse.]
   1. The science which treats of myths; a treatise on myths.
      [1913 Webster]

   2. A body of myths; esp., the collective myths which describe
      the gods of a heathen people; as, the mythology of the
      Greeks.
      [1913 Webster]