Source : Webster's Revised Unabridged Dictionary (1913)

Officiant \Of*fi"ciant\, n. [L. officians, p. pr. See
   {Officiate}.] (Eccl.)
   The officer who officiates or performs an office, as the
   burial office. --Shipley.

Source : WordNet®

officiant
     n : a clergyman who officiates at a religious ceremony or
         service