The Collaborative International Dictionary of English v.0.48:

Mythologic \Myth`o*log"ic\, Mythological \Myth`o*log"ic*al\, a.
   [L. mythologicus: cf. F. mytholigique.]
   1. Of or pertaining to mythology or to myths; as,
      mythological creatures. -- Myth`o*log"ic*al*ly, adv.
      [1913 Webster]

   2. based on or told of in traditional stories; lacking
      factual basis or historical validity; mythical; fabulous.

   Syn: fabulous, mythic, mythical.
        [WordNet 1.5]