Actor-proof - A play with such a great part that no actor can possibly fail playing it.
Ad Lib - Improvising lines until you remember what it is you are supposed to say.
Apron - This is the part of the stage that sticks out past the curtain line, closest to the audience.
Balcony - Once called "the gallery," this is the projecting platform that holds seats above the stage level.
Billing - The listing of actorsí names in ads for the show. Rank is accomplished by the order, as well as size and style of type used.
Blocking - Physical movement of the performers during a show.
Booth - This is the "control room" where the light board operator runs the show. The stage manager might be in the booth or else in the wings.
Break a Leg - Actors (a superstitious bunch) say this to each other when they mean "good luck," on the idea that whatever you say, the opposite will happen. You NEVER wish an actor good luck--unless you want them to really break a leg!
Call Board - The bulletin board backstage where "calls," telegrams, and the closing notice is posted.
Cameo Role - A small theatrical role usually performed by a well-known actor and often limited to a single scene; any brief appearance.
Call - The time an actor is required to be in the theatre before a show. Usually, the call is half an hour before curtain time.
Cheesecake - Photographs of actresses who display attractive areas of their anatomy for publicity purposes.
Chewing the Scenery - The description of zealous overacting.
Cues - If you're an actor, your cue is the line that comes before yours. To "pick up the cues" means to shorten the space between lines and quicken the pace of a scene.
Cattle Call - An open audition where hundreds of actors show up to get a five minute audition.
Eleven O'Clock Number - In a musical, this is a big number toward the end of the second act, usually for the star. In the old days when shows started at eight thirty or even later, this song usually came around eleven o'clock.
Dead House - An unresponsive audience.
Deck - The physical floor, the bare boards of the stage.
Farthingales - A support (as of hoops) worn especially in the 16th century beneath a skirt to expand it at the hipline
The Flies - This is the area above the stage where scenery is rigged and hung. When scenery lifts off the stage in a scene change, it stays in "the flies" until it's needed again. The rigging system is counterweighted and balanced to keep the heavy scenery safely suspended high in the air.
Fol-de-rol - Frivolities, nonsense
Fume like Vesuvius - To be in a state of excited irritation or anger, in a manner resembling the Italian volcano, Vesuvius
George Spelvin - The fictitious name used in the program that indicates that either an actor did not want to use his real name or is playing more than one role and this fact can't be revealed to the audience.
Go Up - If you forget your lines, you've "gone up."
Green Room - This is the room where actors can rest when they are not onstage. They aren't always green, although that was always considered a restful color.
The Grid - This is the name for the area above the stage
where all the stage lights are located. The lights are attached to suspended
beams called "electrics."
Gypsy - A term applied to a chorus member in a musical, but only to a dancer, never to a singer.
Haberdasher - A dealer in menís furnishings
Half-Hour - The warning given to the actors thirty minutes before curtain time.
Hoofer - A professional dancer.
House - The part of the theatre where the audience sits. An appreciative audience is called a "good house," and if it's packed, it's a "full house." People who work in this part of the theatre, like the ushers or the people in the box office, are called "front of house staff."
House Seat - Tickets in the best section of the orchestra reserved for people connected with the production.
I Killed Them - When the actor did very well on stage and the audience loved the performance.
Laying an Egg - A phrase introduced by a monologist named James Thornton, after he told a joke that the audience did not laugh at.
Mezzanine - This term comes from the Italian word for "middle." It refers to the lowest balcony in a theatre (if there is more than one).
Money Note - The strongest note in an actor's singing range. When you audition, you want to make sure you show off your money note.
The Orchestra - This is the term for the seating located on the lowest level. The term actually comes from the Greek word "orcheisthai," which was the area in front of the stage in the theatres of ancient Greece.
Papering the House - Giving away free tickets so that the theater is full and gives the appearance of a hit show.
The Pit - This is the lowered area in front of the stage where the orchestra musicians play. Usually you can see the conductor--his head or his hands stick out just a little on top so the actors onstage can see him. In some theatres, the orchestra is actually under the stage or even in the basement.
The Road - Everything outside of New York. When a show tours, you "take it on the road."
Shtick - A sure-fire piece of "business," also known as stage action, that gets a laugh or applause from the audience.
SRO - Standing room only or sold right out.
Stage Door - The actors and technicians don't enter the theatre through the lobby the way the audience does. They have an entrance that leads directly backstage. The doorman keeps watch, takes messages and packages, and makes sure only show personnel enter the theatre.
Stagehand - A stage worker who handles scenery, properties, or lights.
Stage Left and Stage Right - When an actor moves stage left, he moves to HIS left. So from the audience, stage left is actually on the right side of the stage and vice versa.
Timing - A knowledge of the split second when a line or bit of business will be most effective.
Turkey - A bad show that has failed. Years ago poor shows used to open on thanksgiving day in the hope of making some money during the holiday period.
Upstage and Downstage - It used to be that many theatre stages were "raked," or tilted toward the audience so that the back end was higher than the front end. This way, the audience could see the stage better. So, when an actor moved "downstage," she would have been moving down the tilt, closer to the audience. Nowadays, "downstage" just means toward the audience, and "upstage" means away from the audience. Most actors like to be right "downstage center."
Wings - This is the area just offstage on either side, behind the proscenium, where actors wait just before they come offstage. This is where the term "waiting in the wings" comes from.
Word of Mouth - The things the customers say to their friends and relatives about the show they have seen.
Source: The Language of Show Biz, The Dramatic Publishing Company