Easy :)
A phrase of encouragement given to the actors before a show. Rooted from when the legs of the stage would break from the audience's commotion.
What Is...Break a Leg
A large drapery of painted canvas that provides the rear or upstage masking of a set
What Is...Backdrop
The final act of taking down a set.
What Is...Strike
The conversation between two or more characters.
What Is...Dialogue
The concept of improvising lines not used in the script, basing dialogue more on the character's traits
What Is...Ad Lib
A scene in a play where the drama of the action is resolved.
What Is...Denouement
Produced by the vaporization of various oil-based substances, used to create different effects on stage
What Is...Smoke
Narrow bridges above the stage from which the scenery, props, and lighting equipment can be handled.
What Is...Catwalk
A device for letting the audience what’s on the character’s mind, being most well known as a concept used by Shakespeare
What Is...Soliloquy
When the stage/theater goes dark, usually for a scene change or intermission.
What Is...Blackout
An actor's written movements as to what they’re doing in a certain scene.
What Is...Blocking
Areas to either side of the stage that the audience normally can’t see.
What Is...Wings