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]