n. 演说者, 演讲者, 雄辩家, 原告, 请愿人

[法] 请愿人, 原告, 雄辩者

[ noun ]
a person who delivers a speech or oration
<noun.person>

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.

I am no orator, as Brutus is. --Shak.

Some orator renowned
In Athens or free Rome. --Milton.

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

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}.