Every theatre is unique, but, with few exceptions, theatres, both Western and Asian, can be categorized into four basic forms: arena stage theatres (also referred to as theatre-in-the-round); thrust stage (or open stage) theatres; end stage theatres (of which proscenium theatres are a subset); and flexible stage theatres, also sometimes called black box theatres. The design of all these types is based on the relationship the space establishes between the stage and the house.

Arena theatres are those that have an audience around four sides of the stage. These are often called amphitheatres, island stage theatres, or centre stage theatres, or they are referred to generally as theatre-in-the-round (although the stages can be round, oval, octagonal, square, rectangular, or in a variety of irregular shapes). Arena stages are thought to create a strong sense of community among the audience members and an easy flow of energy between the audience and the actors. They do, however, put major restrictions on the amount and kind of visual spectacle that can be provided for a performance, because scenery more than a few feet tall will block the views the audience members have of the action taking place onstage. In these theatres, scene-changing equipment must be limited primarily to that which can be put under the stage, and special effects are difficult to manage because so little can be hidden from the audience. Arena theatres also complicate the management of the movement pattern for actors (the “blocking”), as they must perform to all sides of the stage without having their backs to any one side for too long a time and without preventing one part of the audience from seeing other actors.

Thrust stage theatres are those in which the stage thrusts out from one side of the space into the midst of the audience. They are also known as open stage theatres and sometimes as courtyard theatres. The audience is most often located around three sides of a thrust stage, though they can be located on two sides opposite each other (as they are in alley stage or transverse stage theatres, sometimes called centre stage theatres) or on two adjoining sides (as they are in L-shaped theatres). Thrust stages are most commonly trapezoidal, semicircular, rectangular, or square. In both arena and thrust stage theatres, some members of the audience will be looking at other members of the audience across the stage, where they will appear as the background to the performance. Thrust stage theatres are therefore thought to share many of the community-building advantages of arena stages. They also make managing the movement patterns of the actors and displaying and changing the scenery less difficult because there is always at least one side of the stage that is not occupied by the audience. Often, arena theatres are designed for easy conversion into thrust stage theatres by way of the removal of one section of audience seating.

End stage theatres are those that have an audience on only one side. Such stages are most often rectangular or square, but they can be triangular (in which case they are called corner stage theatres) or take a variety of irregular shapes that can include side stages (in which case they are referred to as extended stage theatres). End stages are thought to focus the full attention of the audience onto the production. End stages also simplify blocking, allowing actors’ movement patterns to be more easily composed into aesthetically appropriate shapes, and they greatly simplify the display of scenery and special effects. The house of an end stage theatre can be rectangular or take the shape of a fan, leaving all members of the audience facing the same direction. But the house can also be shaped like a bell or a horseshoe or can be semicircular or square and arranged so that some members of the audience can still look across the space at other members of the audience. The significant difference between this form and the arena or thrust stage forms, however, is that in end stages almost all members of the audience must look away from the stage to see their fellow audience members. They therefore do not appear as a background to the performance. For this reason end stage theatres are thought to be less conducive than the other forms to building a sense of community within an audience. End stage theatres may have movable ceiling and walls that can be adjusted to increase or decrease the seating capacity in the house. Some thrust stage theatres can be used as end stage theatres by blocking off the audience’s space on all but one side.

All of the theatre forms discussed so far put the actors and the audience within the same volume of space. But there is one variety of end stage theatre that intentionally puts the stage in a separate volume of space from that occupied by the house: the proscenium, or “Italian style,” theatre. In this form, the stage is separated from the house by a wall with a large arched opening (the proscenium, which can sometimes be rectangular or square) that allows the audience to see through from the house to the stage as if looking through a frame at a large moving picture. Because of this unique feature, the proscenium theatre is often given its own classification. But throughout much of the form’s history, proscenium stages have been fitted with “aprons” or “fore-stages” that carry the stage through the arch into the house and thus make it a variation on the end stage form. Traditionally, actors did most of their performing on the apron, which left the part of the stage behind the arch to be used primarily for scenery and scene-changing equipment. “Calipers,” which are side stages that extend from the main stage through the arch to locations at the right and the left front of the house, have also been used to allow the actors to perform in the same volume of space as that occupied by the audience, at least for small portions of the performance. The proscenium arch theatre was developed in Italy in the 16th and 17th centuries to facilitate the Renaissance’s fascination with perspective and its interest in moving pictures. The form’s greatest advantage continues to be that it allows for the maximum amount of spectacle in performance. The trade-off is that actors must work harder to project their energy from the stage into the house than they do in other theatre forms, because proscenium theatres, especially those without apron stages, tend to make the audience observers of the drama rather than people who experience the drama taking place in their midst. In cultures where observation is considered an appropriate aesthetic quality for theatre, proscenium theatres proliferate; in those where audiences expect to share more of the experience of the drama, they are less popular.

Flexible stage theatres are those that do not establish a fixed relationship between the stage and the house. Also known as black box theatres, laboratory theatres, modular theatres, multiform theatres, free form theatres, or environmental theatres, they can be reconfigured for each performance. They can be put into any of the standard theatre forms or any of the variations of those. They can be made into “surround theatres” (which are sometimes called “total theatres” or “theatre-all-around”), in which the audience sits or stands in the centre and the stage surrounds it on four sides. They can also be made into “promenade” spaces in which the audience follows the actors around to different locations within the space.