The prompt corner or prompt box in a theatre is the location at the side of the stage where the prompt (usually the Stage Manager in US or Deputy Stage Manager in the UK) is located in order to coordinate the performance and prompt the performers when required.[1][2]
Historically, the prompt corner was situated on the (performer's) left side of the stage, therefore Prompt Side (abbreviated to P or PS) and Opposite Prompt (OP) (occasionally called "Off Prompt") are widely used terms for stage left and stage right when blocking a performance.[1]
In some theatres, the prompt desk is situated on stage right, known as a bastard prompt. In this case stage right and left are known as Bastard Side (BS) and Opposite Bastard (OB). This can cause some confusion for actors in touring shows, when the prompt desk is perceived to be on the 'wrong' side of the stage.
The prompt corner is usually equipped with a prompt desk to facilitate the coordination of a performance. It can vary from a small table in the wings, to a complete installation in a separated booth. The prompt desk has space for a copy of the script, and can also include some, all or none of the following features: