e ‧ pon ‧ y ‧ mous /ɪˈpɒnəməs, ɪˈpɒnɪməs $ ɪˈpɑː-/ BrE AmE adjective [only before noun]
[ Date: 1800-1900 ; Language: Greek ; Origin: eponymos , from epi- ( ↑ epicenter ) + onyma 'name' ]
the eponymous character in a book, film, or play is the character whose name is in its title:
Hester, the book’s eponymous heroine