The Collaborative International Dictionary of English v.0.48:

Prelate \Prel"ate\, v. i.
   To act as a prelate. [Obs.]
   [1913 Webster]

         Right prelating is busy laboring, and not lording.
                                                  --Latimer.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Prelate \Prel"ate\ (?; 48), n. [F. pr['e]lat, LL. praelatus, fr.
   L. praelatus, used as p. p. of praeferre to prefer, but from
   a different root. See Elate.]
   A clergyman of a superior order, as an archbishop or a
   bishop, having authority over the lower clergy; a dignitary
   of the church.
   [1913 Webster]

   Note: This word and the words derived from it are often used
         invidiously, in English ecclesiastical history, by
         dissenters, respecting the Established Church system.
         [1913 Webster]

               Hear him but reason in divinity, . . .
               You would desire the king were made a prelate.
                                                  --Shak.
         [1913 Webster]

WordNet (r) 3.0 (2006):

prelate
    n 1: a senior clergyman and dignitary [syn: archpriest,
         hierarch, high priest, prelate, primate]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "prelate":
   Grand Penitentiary, Holy Father, abuna, antipope, archbishop,
   archdeacon, archpriest, bishop, bishop coadjutor, canon, cardinal,
   cardinal bishop, cardinal deacon, cardinal priest, chaplain,
   coadjutor, curate, dean, diocesan, ecclesiarch, exarch, hierarch,
   high priest, metropolitan, papa, patriarch, penitentiary, pontiff,
   pope, prebendary, primate, rector, rural dean, subdean, suffragan,
   vicar



Bouvier's Law Dictionary, Revised 6th Ed (1856):

PRELATE. The name of an ecclesiastical officer. There are two orders of
prelates; the first is composed of bishops, and the second, of abbots,
generals of orders, deans, &c.



The Devil's Dictionary (1881-1906):

PRELATE, n.  A church officer having a superior degree of holiness and
a fat preferment.  One of Heaven's aristocracy.  A gentleman of God.