The Collaborative International Dictionary of English v.0.48:

Repercussion \Re`per*cus"sion\ (-k?sh"?n), n. [L. repercussio:
   cf. F. r['e]percussion.]
   1. The act of driving back, or the state of being driven
      back; reflection; reverberation; as, the repercussion of
      sound.
      [1913 Webster]

            Ever echoing back in endless repercussion. --Hare.
      [1913 Webster]

   2. (Mus.) Rapid reiteration of the same sound.
      [1913 Webster]

   3. (Med.) The subsidence of a tumor or eruption by the action
      of a repellent. --Dunglison.
      [1913 Webster]

   4. (Obstetrics) In a vaginal examination, the act of
      imparting through the uterine wall with the finger a shock
      to the fetus, so that it bounds upward, and falls back
      again against the examining finger.
      [1913 Webster]

WordNet (r) 3.0 (2006):

repercussion
    n 1: a remote or indirect consequence of some action; "his
         declaration had unforeseen repercussions"; "reverberations
         of the market crash were felt years later" [syn:
         repercussion, reverberation]
    2: a movement back from an impact [syn: recoil,
       repercussion, rebound, backlash]