celebrant

(sĕlˈə-brənt)

noun

1. a. A person who participates in a religious ceremony or rite.
   b. A person who officiates at a religious or civil ceremony or rite, especially a wedding.
   c. In some Christian churches, the cleric officiating at the celebration of the Eucharist.
2. A participant in a celebration.

Usage Note: Although celebrant is most often used to describe an official participant in a religious ceremony or rite, a majority of the Usage Panel accepted the use of celebrant to mean “a participant in a celebration” in an earlier survey. Still, while New Year's Eve celebrants may be an acceptable usage, celebrator is an uncontroversial alternative in this more general sense.