Source : Webster's Revised Unabridged Dictionary (1913)

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.

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

Source : WordNet®

mythology
     n 1: myths collectively; the body of stories associated with a
          culture or institution or person
     2: the study of myths