The Collaborative International Dictionary of English v.0.48:

Eponymous \E*pon"y*mous\, a. [Gr. ?; 'epi` upon, to + ? for ?
   name.]
   Relating to an eponym; giving one's name to a tribe, people,
   country, and the like.
   [1913 Webster]

         What becomes . . . of the Herakleid genealogy of the
         Spartan kings, when it is admitted that eponymous
         persons are to be canceled as fictions?  --Grote.
   [1913 Webster]

WordNet (r) 3.0 (2006):

eponymous
    adj 1: being or relating to or bearing the name of an eponym
           [syn: eponymous, eponymic]