There are different types of theatres, but they all have three major parts in common. Theatres are divided into two main sections, the house and the stage; there is also a backstage area in many theatres. The house is the seating area for guests watching a performance and the stage is where the actual performance is given. The backstage area is usually restricted to people who are producing or in the performance.
Types of theatres
Arena: A large open door with seating capacity for very large groups. Seating layouts are typically similar to the theatre in the round, or proscenium (though the stage will not have a proscenium arch. In almost all cases the playing space is made of temporary staging (risers) and is elevated a few feet higher than the first rows of audience. Black box theatre: An unadorned space with no defined playing area. Often the seating is not fixed allowing the room to be re-configured for the demands of a specific production. Typically the seating and performance space are on the same level. Proscenium: The audience directly faces the playing area which is separated by a portal called the proscenium arch. Theatre in the round: The playing area is surrounded by audience seating on all sides. Thrust: The playing area protrudes out into the house with the audience seating on 3 sides. Traverse: The elongated playing area is surrounded by audience seating on two sides. Similar in design to a fashion show runway.
Stage
The area of the theatre in which the performance takes place is referred to as the stage.
Stage directions or stage positions
In order to keep track of how performers and set pieces move around the space, the stage is divided up into sections oriented based on the performers perspective to the audience. Movement is choreographed by blocking which is organized movement on stage created by the director to synchronize the actor's movement onstage in order to use these positions.
Upstage: The area of the stage furthest from the audience. Downstage: The area of the stage closest to the audience. Stage Left: The area of the stage to the performer's left, when facing downstage (i.e. towards the audience). Stage Right: The area of the stage to the performer's right, when facing downstage (i.e. towards the audience). Center Stage: The center of the playing (performance) area. Center Line: An imaginary reference line on the playing area that indicates the exact center of the stage, travelling from up to downstage. Onstage: The portion of the playing area visible to the audience. Offstage: The area surrounding the playing space not visible to the audience. Typically this refers to spaces accessible to the performers but not the audience, such as the wings, crossovers, and voms.
Note that for performance spaces with audiences in more than one orientation, typically one direction is arbitrarily denoted as "downstage" and all other directions reference that point.