I got these stage terms from NYCastings.com and figured these terms can always be revisited. Feel free to print this out and put it on your fridge or tape it on your mirror.
Common Theater Terms
Auditions: Readings before a director to determine casting of a play.
Call Backs: An additional audition for the final actors being considered. Similar to semifinals in sports.
Clear the Stage: A direction given to all actors, musicians, and technicians to leave the stage area prior to the beginning of a play.
Places: The direction for all actors, musicians, and technicians to go to their proper position and be ready for the beginning of a play or scene.
Strike: Taking down, changing out and putting away costumes, props and sets after a production.
Run Through: An uninterrupted rehearsal of a scene, act, or the entire play.
Curtain Call/Bows: The carefully choreographed appearance of actors on stage after the performance to acknowledge the applause of the audience.
Heads Up!: A term of warning used to call attention to overhead danger. Technical Elements
Flats: Muslin or plywood covered frames used to build the walls of a stage setting.
Props: Small hand held items used by actors to create the period, character or setting.
Platforms: Wooden units joined together to build the floors for a stage setting.
Costumes: The clothing worn by the actors that helps determine character, time, theme and mood.
Mask: A term used meaning “to hide.” Also, a covering for an actors face that disguises or changes their character. often made out of leather, plastic or paper maché.
Dark: A time when all lights are out or the theater is closed.
Stage Manager: Person responsible for the physical set up, actors, and technical cues of a production as it is performed.