Source : Webster's Revised Unabridged Dictionary (1913)

Potentate \Po"ten*tate\, n. [LL. potentatus, fr. potentare to
   exercise power: cf. F. potentat. See {Potent}, a.]
   One who is potent; one who possesses great power or sway; a
   prince, sovereign, or monarch.

         The blessed and only potentate.          --1 Tim. vi.
                                                  15.

         Cherub and seraph, potentates and thrones. --Milton.

Source : WordNet®

potentate
     n : a ruler who is unconstrained by law [syn: {dictator}]