The Collaborative International Dictionary of English v.0.48:

Orator \Or"a*tor\, n. [L., fr. orare to speak, utter. See
   Oration.]
   1. A public speaker; one who delivers an oration; especially,
      one distinguished for his skill and power as a public
      speaker; one who is eloquent.
      [1913 Webster]

            I am no orator, as Brutus is.         --Shak.
      [1913 Webster]

            Some orator renowned
            In Athens or free Rome.               --Milton.
      [1913 Webster]

   2. (Law)
      (a) In equity proceedings, one who prays for relief; a
          petitioner.
      (b) A plaintiff, or complainant, in a bill in chancery.
          --Burrill.
          [1913 Webster]

   3. (Eng. Universities) An officer who is the voice of the
      university upon all public occasions, who writes, reads,
      and records all letters of a public nature, presents, with
      an appropriate address, those persons on whom honorary
      degrees are to be conferred, and performs other like
      duties; -- called also public orator.
      [1913 Webster]

WordNet (r) 3.0 (2006):

orator
    n 1: a person who delivers a speech or oration [syn: orator,
         speechmaker, rhetorician, public speaker,
         speechifier]

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

ORATOR, practice. A good man, skillful in speaking well, and who employs a
perfect eloquence to defend causes either public or private. Dupin,
Profession d'Avocat, tom. 1, p. 19..
     2. In chancery, the party who files a bill calls himself in those
pleadings your orator. Among the Romans, advocates were called orators.
Code, 1, 8, 33, 1.