The Collaborative International Dictionary of English v.0.48:

Reminiscence \Rem`i*nis"cence\ (r?m`?-n?s"sens), n. [F.
   r['e]miniscence, L. reminiscentia.]
   1. The act or power of recalling past experience; the state
      of being reminiscent; remembrance; memory.
      [1913 Webster]

            The other part of memory, called reminiscence, which
            is the retrieving of a thing at present forgot, or
            but confusedly remembered.            --South.
      [1913 Webster]

            I forgive your want of reminiscence, since it is
            long since I saw you.                 --Sir W.
                                                  Scott.
      [1913 Webster]

   2. That which is remembered, or recalled to mind; a statement
      or narration of remembered experience; a recollection; as,
      pleasing or painful reminiscences.
      [1913 Webster]

   Syn: Remembrance; recollection. See Memory.
        [1913 Webster]

WordNet (r) 3.0 (2006):

reminiscence
    n 1: a mental impression retained and recalled from the past
    2: the process of remembering (especially the process of
       recovering information by mental effort); "he has total
       recall of the episode" [syn: recall, recollection,
       reminiscence]

Moby Thesaurus II by Grady Ward, 1.0:

33 Moby Thesaurus words for "reminiscence":
   anamnesis, anecdotes, commitment to memory, exercise of memory,
   flashback, hindsight, learning by heart, looking back, memoir,
   memoirs, memories, memorization, memorizing, memory, recall,
   recalling, recollecting, recollection, reconsideration,
   reexperiencing, reflection, reflections, reliving, remembering,
   remembrance, retrospect, retrospection, review, revival, rote,
   rote memory, study, youth