What does actor mean?
The definition of actor
Ac”tor, n.
Etym: [L. actor, fr. agere to act.]

1 One who acts, or takes part in any affair; a doer.
2 A theatrical performer; a stageplayer. After a well graced actor leaves the stage. Shak.
3 (Law)

(a) An advocate or proctor in civil courts or causes. Jacobs.
(b) One who institutes a suit; plaintiff or complainant.