1. Centerline
  2. Plaster line
  3. Proscenium arch
  4. Arena
  5. Thrust
  6. Apron
  7. Downstage
  8. Upstage
  9. Stage right
  10. Center stage
  11. Stage left
  12. Offstage
  13. On stage
  14. Best seat in the house
  15. Worst seat in the house
  16. Sightlines
  17. Orchestra pit
  18. Stage floor
  19. Show deck
  20. Main curtain
  21. Pipe batten
  22. Battens
  23. Arbor
  24. Lift lines
  25. Weights
  26. Guide rails
  27. Operating line
  28. Rope lock
  29. Wings
  30. Masking
  31. Border
  32. Leg
  33. Backdrop
  34. Grommet
  35. Webbing
  36. Side hem
  37. Pipe pocket
  38. Pin rail
  39. Sandbag
  40. Grid
  41. Loft block
  42. Head block
  43. Tension block
  44. Traps
  45. Trap room

1. What is a Center Line?

The center line in a performing arts theater is a critical element for orientation and staging. It runs from the back of the stage to the front, directly down the middle, aligning with the center of the proscenium arch. Historically, this line has served as a key reference point for actors, set designers, and stagehands to ensure symmetry and precision in placing scenic elements, props, and actors. It is fundamental for maintaining balance in the visual composition of a performance.

2. What is a Plaster Line?

A plaster line is an imaginary line that runs across the stage at the back face of the proscenium arch. This line is perpendicular to the center line and is a crucial reference point in technical theater. It helps determine the placement of scenery, lighting, and other stage elements. The term originates from when theater facades were commonly finished with plaster, and this line would often align with a physical plaster feature.

3. What is a Proscenium Arch?

The proscenium arch is the architectural feature that frames the front of the stage and separates it from the auditorium in a traditional theater setting. Its historical roots can be traced back to ancient Greek and Roman theaters. The proscenium arch creates a “window” through which the audience views the performance, and it often serves as a structural element to support curtains, lighting, and scenery.

4. What is an Arena?

An arena in the context of performing arts refers to a theater configuration where the audience surrounds the stage area. This setup dates back to ancient Roman amphitheaters used for gladiatorial contests. In contemporary theater, this layout is sometimes called “theatre-in-the-round” and is prized for its intimacy and engagement with the audience.

5. What is a Thrust?

A thrust stage extends into the audience on three sides and is connected to the background stage area. This type of stage has been used historically since the Elizabethan era, most notably in Shakespeare’s Globe Theatre. The thrust stage design allows for greater intimacy between performers and audience members, with viewers feeling more immersed in the action.

6. What is an Apron?

An apron is that part of a stage that extends beyond the proscenium arch and into the audience or orchestra pit area. Historically, aprons were more common when stages were deeper and more rectangular. Modern times, aprons can be used for closer audience interaction or additional performance space.

7. What is Downstage?

Downstage refers to the area of the stage closest to the audience. Historically, this term comes from the time when stages were raked (slanted) upwards away from the audience; thus, moving “down” meant moving towards the audience. Even on flat stages, this term remains a directional cue for performers and crew.

8. What is Upstage?

Conversely, upstage is the part of the stage furthest from the audience. The term also originates in raked stages where moving “up” meant walking up a slope away from viewers. It has also led to the term “upstaging” when one actor moves to this area, unintentionally (or intentionally) drawing focus from another actor.

9. What is Stage Right?

Stage right refers to the right side of the stage from an actor’s perspective when facing the audience. This directional term helps performers and crew navigate the stage during rehearsals and performances. The distinction between stage right and house right (the audience‚Äôs right) is crucial for clear communication in theater.

10. What is Center Stage?

Center stage denotes the middle area of the stage and is considered a focal point for action within a performance. It is equidistant from both sides of the stage and often serves as a powerful position for key moments in theater productions.

11. What is Stage Left?

Stage left is to an actor’s left when they are looking at the audience, mirroring stage right. It’s another fundamental directional term used in staging and choreography to ensure precise movements and placements during a theatrical production.

12. What is Offstage?

Offstage refers to any area not visible to the audience, including the wings and backstage areas where actors wait before making their entrances or where props are stored between scenes. The term highlights the division between the performance space and behind-the-scenes operations essential to theatrical productions.

13. What is On Stage?

On stage describes any part of the theater visible to the audience during a performance. This includes all areas within view where actors perform and the scenery is displayed, encompassing everything within the proscenium arch in traditional theaters.

14. What is the Best Seat in the House?

The best seat in the house is a subjective term that generally refers to seating locations within a theater that offer optimal viewing experiences based on visual and acoustic quality. Historically, these seats have been associated with higher social status or premium pricing due to their desirable location.

15. What is the Worst Seat in the House?

Conversely, the worst seat in the house refers to seats with obstructed views or poor acoustics that diminish the quality of the viewing experience for audience members. These seats are often further from the stage or awkwardly angled, leading to less favorable impressions of performances.

16. What are Sightlines?

Sightlines are imaginary lines from an observer’s eye to a stage or performance area that clearly determine what can be seen. Ensuring good sightlines is crucial in theater design as it affects how well an audience can view a production without obstruction.

17. What is an Orchestra Pit?

The orchestra pit is usually located at the front of a theater stage and below audience level, accommodating musicians during a performance. Its design allows for unobstructed sound projection while keeping musicians out of sightlines, maintaining focus on stage action.

18. What is a Stage Floor?

The stage floor is the surface on which performances occur within a theater space. It can be designed to accommodate various needs, such as dance, which may require sprung floors to reduce injury risk, or it may include traps for special effects or scene changes.

19. What is a Show Deck?

A show deck is a temporary floor laid over a theater’s existing stage floor for a specific production. It allows designers to create custom surfaces suited for particular scenic designs or action sequences without permanently altering the original stage floor.

20. What is a Main Curtain?

The main curtain, also known as a grand drape or house curtain, is typically located just behind the proscenium arch and can be opened or closed to reveal or conceal the stage from the audience’s view. Historically, heavy velvet was often used for its rich appearance and sound-dampening qualities.

21 What is a Pipe Batten?

A pipe batten, or simply batten, refers to a horizontal pipe suspended over a stage from which lighting fixtures, scenery, or curtains can be hung. This term has been part of theatrical jargon since rigging systems became integral to theater design.

22. What are Battens?

Battens are long pipes or bars from which lights, scenery, or curtains are hung in a theater setting. They are part of a fly system for raising and lowering elements during scene changes or between productions.

23. What is an Arbor?

An arbor in theatrical rigging is a frame that holds weights counterbalancing battens’ loads in a fly system, allowing for smooth raising and lowering of suspended elements such as curtains or scenery.

24. What are Lift Lines?

Lift lines are part of a theater’s fly system; they are cables or ropes that connect battens to counterweights or motorized hoists, enabling controlled vertical movement of scenery, drops, or lighting instruments.

25. What are Weights?

Weights in theater refer to counterbalances used in fly systems to ensure that battens with attached scenic elements or lighting can be raised and lowered easily and safely by stagehands or automated systems.

26. What are Guide Rails?

Guide rails are used in theaters to ensure that moving elements such as curtains or scenic pieces travel in a straight path when raised or lowered by a fly system, preventing sway or unintended movement.

27. What is an Operating Line?

An operating line refers to ropes or cables stagehands use to manually control flying elements, such as curtains or scenery within a theater’s fly system.

28. What is a Rope Lock?

A rope lock is a device in a fly system that secures operating lines in place once scenery or curtains have been raised or lowered to their desired position on stage, ensuring safety and stability during performances.

29. What are Wings?

Wings are areas on either side of a theater’s stage out of view from the audience, where actors prepare for entrances and where props can be kept ready for use during performances.

30. What is Masking?

Masking refers to curtains, flats, or other materials used in theaters to block off backstage areas from audience view, control light spillage, and frame the performance area.

31. What is a Border?

A border, in theater terms, is a wide horizontal drape that spans across the top of the stage used for hiding lighting instruments from view and creating a visual limit on vertical space within scenic designs.

32. What is a Leg?

Legs in theater are narrow vertical drapes used on either side of the stage to mask offstage areas from audience sightlines while also helping manage acoustics within performance spaces.

*Borders vs. Teasers, Legs vs. Torms, and Tabs, aka Side Tabs.

Regarding theater stage masking, the following terms are often used interchangeably. Here are the actual definitions of these terms.


In theater, a border (often referred to as a teaser in some contexts) is a wide, horizontal drape or curtain that runs across the top of the stage. Its primary function is to mask or hide lighting instruments and the upper stage machinery from the audience’s view. Borders are typically used in sequence across the width of the stage and are hung from battens to create a false ceiling or “teaser line,” which helps define the top limit of the stage for the audience.


A teaser is a specific type of border. While both are used to mask the upper part of the stage, a teaser is usually the first, and sometimes larger, curtain just upstage of the proscenium arch. It is adjustable in height and can be lowered or raised to alter the audience’s view of the vertical stage dimension. Although “border” and “teaser” can be used interchangeably, in a properly outfitted theater, a teaser specifically refers to an adjustable horizontal masking curtain that allows for more control over the audience’s sightlines.


Legs are narrow, vertical drapes used in theater to mask the sides of the stage. They help to conceal offstage areas, equipment, and performers waiting to make their entrances. Legs are hung parallel to the proscenium arch and are often paired with borders to create a complete masking frame around the visible stage area.


Torms, short for tormentors, are similar to legs in that they are vertical pieces of stage drapery. However, torms are typically positioned just upstage of the proscenium arch and can be used to narrow the visible stage area from the perspective of the audience. They are similar to legs but are usually more substantial and sometimes part of a built structure rather than just drapery.

Tabs, aka Side Tabs

Tabs, also known as side tabs or tab curtains, are curtains on the sides of the stage that can be drawn to mask the wings or be used for entrances and exits by performers. They are similar in function to legs but differ in that they can be opened or closed, whereas legs are stationary. Tabs provide flexibility in revealing or concealing different parts of the offstage area and can be used creatively for dramatic effect in a performance.

While these terms are related and sometimes used interchangeably due to their similar purposes (masking parts of the stage), each has its specific application. Borders and teasers are horizontal drapes that define the top limit of the viewing area; legs and torms are vertical drapes that mask the sides but differ in their positioning and structural nature; tabs (or side tabs) are also vertical but have the functionality of being drawn open or closed. In a proper scenario, each term refers to the specific type of masking required by the design of the stage and production needs.

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