Source : Webster's Revised Unabridged Dictionary (1913)

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.

Source : WordNet®

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