Source : Webster's Revised Unabridged Dictionary (1913)

Hierarch \Hi"er*arch\, n. [LL. hierarcha, Gr. ?; "iero`s sacred
   (akin to Skr. ishiras vigorous, fresh, blooming) + ? leader,
   ruler, fr. ? to lead, rule: cf. F. hi['e]rarque.]
   One who has high and controlling authority in sacred things;
   the chief of a sacred order; as, princely hierarchs.
   --Milton.

Source : WordNet®

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