celebrant

from WordNet (r) 3.0 (2006)

celebrant
    n 1: a person who is celebrating [syn: {celebrant},
         {celebrator}, {celebrater}]
    2: an officiating priest celebrating the Eucharist

from The Collaborative International Dictionary of English v.0.48

Celebrant \Cel"e*brant\, n. [L. celebrans, p. pr. of celebrare.
   See {Celebrate}.]
   One who performs a public religious rite; -- applied
   particularly to an officiating priest in the Roman Catholic
   Church, as distinguished from his assistants.
   [1913 Webster]