The Collaborative International Dictionary of English v.0.48:

memorabilia \mem`o*ra*bil"i*a\, n. pl. [L., fr. memorabilis
   memorable. See Memorable.]
   1. Things remarkable and worthy of remembrance or record;
      also, the record of them.
      [1913 Webster]

   2. Mementos of past events; souvenirs.
      [PJC]

WordNet (r) 3.0 (2006):

memorabilia
    n 1: a record of things worth remembering

Moby Thesaurus II by Grady Ward, 1.0:

72 Moby Thesaurus words for "memorabilia":
   Clio, Muse of history, adventures, ana, annals, archives,
   autobiography, biographical material, biographical records,
   biographical sketch, biography, case history, chronicle,
   chronicles, chronology, commemoration, confessions,
   curriculum vitae, diary, experiences, favor, fortunes,
   government archives, government papers, great doings, hagiography,
   hagiology, historical documents, historical records,
   historiography, history, journal, keepsake, legend, life,
   life and letters, life records, life story, martyrology,
   matter of concern, matter of importance, memento, memento mori,
   memoir, memoirs, memorial, memorials, memories, necrology,
   obituary, object of note, papers, parish rolls, photobiography,
   point of interest, presidential papers, profile, public records,
   record, relic, remembrance, remembrancer, resume,
   something special, souvenir, story, theory of history,
   thing of interest, token, token of remembrance, trophy,
   vital concern