actor

Etymology

Middle English actour, from Anglo-Norman actor, Middle French actor, and their source, Latin āctor (“doer”), from agō (“to do”). Equivalent to act + -or. Cognate with Ancient Greek ἄκτωρ (áktōr, “leader”), from ἄγω (ágō, “lead, carry, convey, bring”).

noun

1. (obsolete, law) Someone who institutes a legal suit; a plaintiff or complainant.
2. (obsolete) Someone acting on behalf of someone else; a guardian.
3. Someone or something that takes part in some action; a doer, an agent.
   Never, my dear Bethel, did the most feverish dreams of fiction produce scenes more painful, or more terrific, than the real events to which I have been an actor, since the date of my last letter. 1792, Charlotte Smith, Desmond, Broadview, published 2001, page 373
4. A person who acts a part in a theatrical play or (later) in film or television; a dramatic performer.
   Seems like everyone's an actor / Or they're an actor's best friend / I wonder what was wrong to begin with / That they should all have to pretend 1991, Ani DiFranco (lyrics and music), “Anticipate”, in Not So Soft
   Exactly. Marijuana is something we just all gradually decided is okay, like Mark Wahlberg as a serious actor. “You know what? Sure, I’ve decided I’m fine with that.” Apr 2 2017, “Marijuana”, in Last Week Tonight with John Oliver, season 4, episode 7, John Oliver (actor), via HBO
   "I'm an actress -- actor, as we have to say these days." 2010, Peter Corris, Torn Apart, Allen and Unwin, page 88
5. (obsolete, Ancient Rome) An advocate or proctor in civil courts or causes.
6. (grammar) The subject performing the action of a verb.
7. (software engineering) The entity that performs a role (in use case analysis).