The Collaborative International Dictionary of English v.0.48:

Celebration \Cel`e*bra"tion\, n. [L. celebratio.]
   The act, process, or time of celebrating.
   [1913 Webster]

         His memory deserving a particular celebration.
                                                  --Clarendok.
   [1913 Webster]

         Celebration of Mass is equivalent to offering Mass
                                                  --Cath. Dict.
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         To hasten the celebration of their marriage. --Sir P.
                                                  Sidney.
   [1913 Webster]

WordNet (r) 3.0 (2006):

celebration
    n 1: a joyful occasion for special festivities to mark some
         happy event [syn: celebration, jubilation]
    2: any joyous diversion [syn: celebration, festivity]
    3: the public performance of a sacrament or solemn ceremony with
       all appropriate ritual; "the celebration of marriage" [syn:
       celebration, solemnization, solemnisation]