The Collaborative International Dictionary of English v.0.48:

Carillon \Car"il*lon\, n. [F. carillon a chime of bells,
   originally consisting of four bells, as if fr.. (assumed) L.
   quadrilio, fr. quatuer four.]
   [1913 Webster]
   1. (Mus.) A chime of bells diatonically tuned, played by
      clockwork or by finger keys.
      [1913 Webster]

   2. A tune adapted to be played by musical bells.
      [1913 Webster]

WordNet (r) 3.0 (2006):

carillon
    n 1: set of bells hung in a bell tower
    2: playing a set of bells that are (usually) hung in a tower
       [syn: bell ringing, carillon, carillon playing]