THEATRICAL GLOSSARY
Welcome to the LVH Entertainment Systems' terms and definition glossary.
Good communication is the key to understanding. As with any industry, theatrical lighting and rigging have their own terms and definitions. To avoid confusion and to help you communicate your needs, we have developed this list of terms.
We hope they prove useful to you.
(NOTE: Use your browser's "Find" feature to quickly go to terms or definitions).
B C D E F G H I L M O P R S T U V-W
Acting Area - The portion of the stage proper, excluding the forestage, viewed by the audience during a given scene.
Ante-Pro—Lighting position in the auditorium ceiling for illuminating the apron and front part of the stage. Also known as the front-of-house lighting position.
Apron—Part of the stage that protrudes down stage of the proscenium, towards the audience. Also known as forestage or thrust.
Arbor—A carriage or rack that contains counterweight, usually flame cut steel or cast iron, in sufficient quantity to balance a load.
Audience—The area of the theater where visitors sit to view a performance.
Austrian Curtain—A curtain that is raised (opened) with brailed lifting lines, gathering vertically in folds. It is sewn with both vertical and horizontal fullness.
Backstage—All areas related to, but not on, the stage, including dressing rooms, technical areas, etc.
Batten—A pipe or bar, usually made from 1-1/2" I.D. steel pipe, from which scenery, lights and curtains are hung.
Beam Clamp—A device attached to the flange of a steel beam or channel, from which other equipment is hung or attached to the beam.
Belaying Pin—A wood or steel rod, approximately 1" in diameter, inserted into a hole in a pin rail, that secures ropes attached to a load.
Block—Assembly containing a sheave(s), axle and housing. Includes floor block, head block, loft block and others. See block and fall.
Block and Fall—A system of rope and pulleys (blocks) used to mechanically increase lifting or pulling ability of the operator.
Border Curtain—A curtain used to define the top limit of the stage sight line and to mask or hide lights and unused scenery and curtains stored in the loft area.
Brail Curtain—A curtain that is raised (opened) with brail type lift lines and is sewn flat or has horizontal fullness.
Brail Lines—Lifting lines that pass through a row of rings sewn to the back of the curtain and attach at the curtain bottom. The curtain folds up vertically when the lines are pulled.
Bridle—Typically two chains or wire ropes run at an angle to each other to support a batten, third chain or rope. Load ratings must be carefully calculated and observed when using bridles.
Butterfly—Curtain that is pulled aside and upward from one lower edge, without moving the opposite edge of the same piece or half. Also known as tab or tableau curtain.
Cable Guide— Refers to a system that guides an arbor, clew or curtain along a length of cable.
Cable Roller—A roller assembly designed to prevent moving cables from contacting any part of a building or adjacent rigging. Not intended to change cable direction or carry loads.
Capstan Winch— A winch, usually portable, with an un-grooved drum designed to assist in moving heavy loads. An operator wraps a rope around the drum and pulls to tighten the rope on the drum. Friction causes the rope to travel with the rotating drum.
Clew—A device, usually steel plate or iron ring, that allows the transition of a number of lines into one.
Commando Cloth—Napped, inexpensive fabric, popular as studio backdrop and stage cyc set fabric; typically black. Also known as duvetyne or velourette.
Compensating Line—A system of light and heavy chains or cables that balances lift line weight as it transfers from the batten to the arbor side of a moving counterweight set.
Compound Arbor—An arbor that uses mechanical advantage to allow the batten to travel twice the distance as the arbor. This method is used when the arbor travel is restricted, but has the disadvantage of requiring twice as many slip weights as a standard arbor to balance the set.
Connector Strip—An electrical raceway with multiple circuits and receptacles used to supply power to stage lighting fixtures.
Contour Curtain—A brail or Austrian curtain rigged so that each lift line may be operated separately to form different shaped openings.
Counterweight Arbor—See Arbor.
Counterweight Set—The complete system, comprised of a counterweight arbor hand line, tension block, head block, lift lines, loft blocks and rigging batten. Also known as a rigging set.
Counterweight—Weights, usually flame cut steel, that are placed in counterweight arbors to balance the weight of loads hung on battens.
Cross-Over—Corridor formed between a back curtain or backdrop and the rear wall, so performers or stage hands may cross from one side of the stage to the other, unseen by the audience, usually while a scene is in progress.
Cyclorama—The curtain at the rear of the performance area, usually without pleating or fullness, used to represent the sky or distant areas. Also the borders, legs, and drops used to define the limits of a performance area.
Dash Pot—An adjustable, hydraulic ram that smoothly slows and stops a moving object. Normally used on fire curtain rigging to slow the last few feet of descent.
Dead End—The end of a rope or part of a device that is not active or load carrying. Also called the bitter end.
Dead Load—The permanent or non-removable part of a system load (i.e. The weight of a batten versus the load hung from it).
Dead-Hung—The suspension of stage equipment, in a fixed position, from non-movable lines.
Double Purchase—A rope or cable that passes from a lifting device over a block, to a second block attached to the load, and tied off at the first block. This line is double purchased. This allows twice as much load to be raised for a given effort, but the rope or cable must be pulled twice as far, so the total work done remains the same. (See Compound Arbor)
Down Stage—A direction, on stage, referenced from the back of the stage towards the audience.
Drop—A hanging fabric piece, typically built of muslin and painted.
Drum Winch—A winch with a grooved drum for managing the cable as it is spooled on and off the drum.
Electrics—A batten dedicated for attaching lighting instruments, usually with a connector strip located above the batten.
Equal Pitch—All grooves on a sheave place the center of the rope or cable at the same distance from the center of the sheave regardless of the diameter of the cables or ropes.
Fire Curtain—Fire-resistive curtain, made of Fiberglas interwoven with small wires for support, designed to rapidly lower and close off the proscenium opening in response to rising temperatures. Required to prevent rapid spread of flames into the audience area in case of fire in a loft stage. In older facilities this is likely to be made of asbestos and, as a result, it is commonly called an asbestos curtain.
Fire Safety Curtain—See Fire Curtain
Fleet Angle—The angle formed between the centerline of a sheave or groove and the direction of travel of the cable or rope coming out of the groove. Maximum allowable fleet angle for counterweight rigging is usually 1½ º.
Floor Block—Pulley mounted at the floor to hold a rope or cable in position. Sometimes called a Tension Block.
Floor Pocket—Electrical distribution device, mounted flush into the stage floor. May contain stage lighting receptacles, utility receptacles or sound or lighting control receptacles.
Fly Gallery—A catwalk above the stage floor from which counterweight and hemp (rope) rigging is operated.
Fly Loft—The space above the stage area that is not visible to the audience.
Fly In—The act of lowering a batten, curtain, drop, electric or set.
Fly Out—The act of raising a batten, curtain, drop, electric or set.
Fullness—Extra fabric that is added to a curtain to be sewn into pleats. 100 percent fullness means that the curtain would be double its finished width before the pleats are made.
Grid (Pipe)—An arrangement of pipes placed in two directions perpendicular to each other, often in a pattern of 4'x 4'squares. Typical in a television studio or black box theatre.
Gridiron (Grid)—An open floor, usually made above the stage area, from steel channels or grating, that is located near the roof steel. It provides mounting locations for rigging equipment and access to that equipment for inspection and maintenance.
Guide—Rollers or slides used to control the movement of rigging devices in tracks or on stretched cables.
Hand Line—A line, usually rope, that is pulled by hand to lift or control the movement of a load. Also known as a purchase line.
Head Block Beams—Structural steel designed to support the head blocks and carry vertical and horizontal loads. Aka, Head Well.
Head Block—Multiple sheave block mounted on the Head Block Beam above a counterweight arbor that changes the direction of lift and operating lines.
Hemp Rigging—A rigging system that employs ropes and sandbags instead of counterweight arbors or other devices. Usually used for temporary rigging.
House Left/Right—The sides of an auditorium as seen by an audience member while facing the stage.
House—General term for the large room where the audience is seated, regardless of the exact type of space (gymnasium, auditorium, church sanctuary, etc.). See "Auditorium."
Idler—A pulley designed to guide/support one or more cables from sagging and rubbing but not to make direction changes in the cable.
Incremental Block—A multi-grooved pulley that supports and changes the direction of cables between the load and the head block and that supports other, more distant, lines in the set.
Index Light—A lighting fixture containing a number of low-wattage lamps, mounted above the locking or pin rail.
Index Strip—A strip mounted on or near lock rail with cards, tape or other means to identify the individual rigging sets.
Lattice Track—A parallel pair of angles or other structural members that act as a track to guide an arbor or clew. Low friction slides or roller guides are placed on both sides of the device to be guided.
Lead (Lift) Line—Support line, running from the arbor, through head and loft blocks to one of several locations on rigging batten.
Leg Curtain—A curtain used to define the side limit of the stage and to mask or hide actors, lights, and unused scenery in the off stage area (wings).
Legs—In pairs, these are side masking curtains, and part of the cyc set.
Leno—Curtain fabric used primarily as a cyclorama fabric.
Lighting Bridge—A walkway across the stage where lights are hung and where they may be adjusted and maintained.
Line Shaft Winch—Winch with a series of cable drums connected to a gearbox by a common shaft used to lift and lower a load.
Live End—The end of a rope or part of a device that is active or load carrying.
Live Load—That part of a system load that may be added or deleted (i.e. Lights or scenery hung from a pipe batten).
Load Brake—A secondary brake that holds the full load in the system, usually in the case of a failure in the system.
Loading Gallery—A platform above the stage floor used to add or remove counterweights from the arbors. Usually located to allow access to the arbors when the battens are at their lowest positions. Sometimes called a Loading Bridge.
Lock Rail—A metal railing designed to support rope locks in a way that allows them to be safely operated. It carries modestly out of balance loads from the rigging system held by rope locks.
Loft Block—A pulley mounted to the gridiron or support steel, through which an individual lead line passes and turns down, going to the rigging batten or load.
Main Curtain—A curtain that is opened to signal the beginning of a performance. The Front Curtain is often used for this purpose.
Masking—A set of curtains or scenic elements used to define the visual limits of a performance area. Also known as a teaser or simply a border.
Mule Block—A pulley used to change the horizontal direction of a line.
Multi-Sheave Block—A block that contains a number of independent sheaves and bearings, usually on a common axle, so that each rope or cable can operate independently.
Off Stage—The stage area that is not a part of the acting area and is not visible to the audience.
Olio Curtain—A curtain located behind the "Front" or "Act" curtain and the "Rear" curtain. Used to close off a portion of the acting area for more intimate presentations. Common in older stages, although largely replaced by mid-stage traveler curtains in new facilities.
On Stage—The portion of the stage area visible to the audience, usually defined by masking curtains, scenery, an orchestra shell, or by lighting.
Orchestra Lift—A platform that is used to adjust the elevation of the musicians in relation to the stage and auditorium. Usually operates within the confines of an orchestra pit.
Orchestra Pit—An area between the stage and audience, usually depressed, where musicians sit, so the audience can hear the music and see the performance over the heads of the musicians.
Orchestra Shell—An enclosure on stage, consisting of walls and a ceiling that reflects sound into the auditorium.
Outrigger—A barrier device, usually built out from the side wall, that protects counterweight arbors from scenery, etc. that may be leaned against them. Can also be used to support the index lights.
Overspeed Brake—A secondary brake designed to halt a load if it exceeds a preset speed.
Pinrail—A rail to which hand lines are secured by tying around a belaying pin.. May also act as a safety railing at the edge of a gallery or walkway.
Pipe Clamp—Clamping device that bolts around a pipe for attachment of chain or cable hangers.
Pipe Grid—See "Grid".
Pitch Diameter—Diameter of a sheave or drum measured from the center line of the cable or rope to be wrapped around it.
Pivot Block—A pulley designed to adjust to structures at odd angles.
Pivoting Device—Rotating device, allowing a side leg to be turned on its vertical axis. Can be mounted to a batten or in a crosstrack.
Plug Box—Electrical distribution device, containing stage lighting circuit receptacles, either flush or on pigtails. Can be permanently mounted or attached to a flexible cable.
Portal—A portal consists of a header or border and legs that can be moved to adjust the size and shape of the proscenium opening to fit various performance needs.
Proscenium Arch—The opening in the proscenium wall through which the audience views a performance. Usually just called the proscenium.
Proscenium Legs—Curtains matching, or for use with, the front curtain, located on both sides in front of the proscenium arch. See also tormentors.
Proscenium Wall—The dividing wall or barrier between audience and the stage.
Raked Stage—A sloped platform that is lower near the audience for better visibility and higher at the rear, providing the illusion of distance. This is the source for the terms "Down Stage" and "Up Stage."
Rope Lock—A clamping device that prevents the hand line of an arbor from accidentally moving. Designed to hold the balanced load in a set at a fixed position.
Safety Chain—A secondary support line, usually of chain, that supports a fire curtain or other device should the primary support cable fail or become slack for any reason. The extra weight of fire curtain safety chains also helps the fire curtain accelerate at the start of its travel.
Sag Bar—A support rail, usually of wood or plastic, that keeps cables from sagging over a horizontal span due to their own weight. Sag bars don't carry any loads. Also see "Cable Roller."
Sandbag—A fabric bag that can be filled with sand and used for weighing down scenery supports. In rope rigging systems, a larger sandbag can be attached to the trim clamp to counterbalance the load hung from the set.
Scrim—A curtain made from a loosely woven special effects fabric that looks solid when lit from the audience side and becomes almost invisible when back lit.
Self-Climbing—A pipe grid or batten that has an integral device for raising and lowering.
Set—A system of cables, pulleys, lifting devices and battens that holds a specific set of scenic elements, curtains or lights.
Sheave—A wheel with a groove around its circumference to support and contain a rope or cable. Sometimes mistakenly called a pulley.
Single Purchase—A rope or cable passing from a lifting device over a block, or series of blocks, to a load is single purchased. Force must be exerted equal to the load to be held or raised.
Smoke Pocket—A metal pocket, usually installed on the proscenium wall, that supports a guide system at the edges of a fire safety curtain and helps prevent smoke passing around the edges of the curtain.
Spot Line—Any special-purpose single line, for either temporary or more permanent use.
Spotline Rigging—A temporary rigging system designed to be easily installed. Often rigged with rope instead of counterweight.
Stage Left / Right—The direction on stage, as perceived by an actor when facing the audience, to his left/right.
Stage Lift—A portion of the stage floor that may be raised or lowered by some type of mechanical lifting device.
Stage—The area where a performance is given.
Straight Lift Curtain—A curtain that can be raised (opened) without folding in any way.
Swivel Block—A pulley that moves or rotates around a fixed point.
Tab—A masking leg that is mounted at right angles to the front of the stage. Also see "Portal."
Tag Line—A line attached to a load to assist in controlling its movement.
T-Bar Wall—The wall made up of Tee Guides and the associated bracing.
Tee Guides—"T" shaped steel or aluminum members placed in parallel rows to guide arbors or clews. Guides may consist of low friction slides or rollers.
Tie-off Bracket—A bracket attached to rigging blocks, gridiron, or other structure to hold wires for guiding clews.
Tormentor Legs—Similar to proscenium legs, except located behind the arch. Sometimes refers to any masking curtains located at the sides.
Traction Drive Winch—Winch with a v-grooved drum that uses friction between cables and the sides of the grooves to engage the pulling cables. Increasing the cable tension causes the cables to jam tighter in the v-grooves.
Travel—The path of moving stage equipment and the distance moved.
Traveler Track—A horizontal guide used to support and operate a curtain, whether a front curtain, rear curtain or mid-stage traveler.
Traveler—A curtain operating on a horizontal track, that can be opened or closed to reveal or mask a portion of the stage.
Trim Chain—A length of chain placed between a lift line and a pipe batten or a batten and a scenic element to connect them and to facilitate minor height adjustment of the load.
Trim Clamp—Device fastened to the hand lines of a manual set to maintain an even trim.
Trim (a)—(1) A load is "in trim" when the equipment load equals the counterbalancing weight.(2) A set or element is trimmed when it has been placed in the desired position within the performance area.
Trim (b)—Adjusting a curtain, drop or other equipment so that it is the proper height and level.
Tripped—A curtain or scenic element is lifted by a second set of lines attached at the bottom or intermediate point on the piece causing it to store in half its normal height. Pulling the lines will cause the piece to fold in half or thirds. Note: If the piece is counterbalanced, the weight balance will shift as the piece is tripped.
Under Hung—Hung from the bottom of a beam or structure.
Under-hung Grid—Gridiron which has loft blocks mounted on the underside of the ceiling, over the grid.
Up Stage—The direction on stage referenced from the audience towards the back of the stage. See "Raked Stage."
Upright Grid—Gridiron that has loft blocks mounted on its upper side. Also called an overhung grid.
Upright—Resting on top of a beam or structure.
Valance—A special border behind the proscenium arch and in front of the front curtain. Usually is the same color and fabric as the front curtain.
Wall Batten—Horizontal structural members to which tee guide tracks are attached. Part of the tee wall.
Wall Knee—Bracket that attaches a wall batten to the building structure. Part of the tee wall.
Well—A reinforced open slot in the grid where the rigging equipment is mounted offering added strength.
Wings—The areas on either side of the stage, beyond the acting area.
Wire Grid—Sometimes called a "Tension Grid". It is formed of woven cables attached to, and supported by, a structural frame.
Wire Guide—Wires placed to control the location and travel of arbors, clews and curtains.
Welcome to the LVH Entertainment Systems' terms and definition glossary.
Good communication is the key to understanding. As with any industry, theatrical lighting and rigging have their own terms and definitions. To avoid confusion and to help you communicate your needs, we have developed this list of terms.
We hope they prove useful to you.
(NOTE: Use your browser's "Find" feature to quickly go to terms or definitions).
B C D E F G H I L M O P R S T U V-W
A
Acting Area - The portion of the stage proper, excluding the forestage, viewed by the audience during a given scene.
Ante-Pro—Lighting position in the auditorium ceiling for illuminating the apron and front part of the stage. Also known as the front-of-house lighting position.
Apron—Part of the stage that protrudes down stage of the proscenium, towards the audience. Also known as forestage or thrust.
Arbor—A carriage or rack that contains counterweight, usually flame cut steel or cast iron, in sufficient quantity to balance a load.
Audience—The area of the theater where visitors sit to view a performance.
Austrian Curtain—A curtain that is raised (opened) with brailed lifting lines, gathering vertically in folds. It is sewn with both vertical and horizontal fullness.
B
Backstage—All areas related to, but not on, the stage, including dressing rooms, technical areas, etc.
Batten—A pipe or bar, usually made from 1-1/2" I.D. steel pipe, from which scenery, lights and curtains are hung.
Beam Clamp—A device attached to the flange of a steel beam or channel, from which other equipment is hung or attached to the beam.
Belaying Pin—A wood or steel rod, approximately 1" in diameter, inserted into a hole in a pin rail, that secures ropes attached to a load.
Block—Assembly containing a sheave(s), axle and housing. Includes floor block, head block, loft block and others. See block and fall.
Block and Fall—A system of rope and pulleys (blocks) used to mechanically increase lifting or pulling ability of the operator.
Border Curtain—A curtain used to define the top limit of the stage sight line and to mask or hide lights and unused scenery and curtains stored in the loft area.
Brail Curtain—A curtain that is raised (opened) with brail type lift lines and is sewn flat or has horizontal fullness.
Brail Lines—Lifting lines that pass through a row of rings sewn to the back of the curtain and attach at the curtain bottom. The curtain folds up vertically when the lines are pulled.
Bridle—Typically two chains or wire ropes run at an angle to each other to support a batten, third chain or rope. Load ratings must be carefully calculated and observed when using bridles.
Butterfly—Curtain that is pulled aside and upward from one lower edge, without moving the opposite edge of the same piece or half. Also known as tab or tableau curtain.
C
Cable Guide— Refers to a system that guides an arbor, clew or curtain along a length of cable.
Cable Roller—A roller assembly designed to prevent moving cables from contacting any part of a building or adjacent rigging. Not intended to change cable direction or carry loads.
Capstan Winch— A winch, usually portable, with an un-grooved drum designed to assist in moving heavy loads. An operator wraps a rope around the drum and pulls to tighten the rope on the drum. Friction causes the rope to travel with the rotating drum.
Clew—A device, usually steel plate or iron ring, that allows the transition of a number of lines into one.
Commando Cloth—Napped, inexpensive fabric, popular as studio backdrop and stage cyc set fabric; typically black. Also known as duvetyne or velourette.
Compensating Line—A system of light and heavy chains or cables that balances lift line weight as it transfers from the batten to the arbor side of a moving counterweight set.
Compound Arbor—An arbor that uses mechanical advantage to allow the batten to travel twice the distance as the arbor. This method is used when the arbor travel is restricted, but has the disadvantage of requiring twice as many slip weights as a standard arbor to balance the set.
Connector Strip—An electrical raceway with multiple circuits and receptacles used to supply power to stage lighting fixtures.
Contour Curtain—A brail or Austrian curtain rigged so that each lift line may be operated separately to form different shaped openings.
Counterweight Arbor—See Arbor.
Counterweight Set—The complete system, comprised of a counterweight arbor hand line, tension block, head block, lift lines, loft blocks and rigging batten. Also known as a rigging set.
Counterweight—Weights, usually flame cut steel, that are placed in counterweight arbors to balance the weight of loads hung on battens.
Cross-Over—Corridor formed between a back curtain or backdrop and the rear wall, so performers or stage hands may cross from one side of the stage to the other, unseen by the audience, usually while a scene is in progress.
Cyclorama—The curtain at the rear of the performance area, usually without pleating or fullness, used to represent the sky or distant areas. Also the borders, legs, and drops used to define the limits of a performance area.
D
Dash Pot—An adjustable, hydraulic ram that smoothly slows and stops a moving object. Normally used on fire curtain rigging to slow the last few feet of descent.
Dead End—The end of a rope or part of a device that is not active or load carrying. Also called the bitter end.
Dead Load—The permanent or non-removable part of a system load (i.e. The weight of a batten versus the load hung from it).
Dead-Hung—The suspension of stage equipment, in a fixed position, from non-movable lines.
Double Purchase—A rope or cable that passes from a lifting device over a block, to a second block attached to the load, and tied off at the first block. This line is double purchased. This allows twice as much load to be raised for a given effort, but the rope or cable must be pulled twice as far, so the total work done remains the same. (See Compound Arbor)
Down Stage—A direction, on stage, referenced from the back of the stage towards the audience.
Drop—A hanging fabric piece, typically built of muslin and painted.
Drum Winch—A winch with a grooved drum for managing the cable as it is spooled on and off the drum.
E
Electrics—A batten dedicated for attaching lighting instruments, usually with a connector strip located above the batten.
Equal Pitch—All grooves on a sheave place the center of the rope or cable at the same distance from the center of the sheave regardless of the diameter of the cables or ropes.
F
Fire Curtain—Fire-resistive curtain, made of Fiberglas interwoven with small wires for support, designed to rapidly lower and close off the proscenium opening in response to rising temperatures. Required to prevent rapid spread of flames into the audience area in case of fire in a loft stage. In older facilities this is likely to be made of asbestos and, as a result, it is commonly called an asbestos curtain.
Fire Safety Curtain—See Fire Curtain
Fleet Angle—The angle formed between the centerline of a sheave or groove and the direction of travel of the cable or rope coming out of the groove. Maximum allowable fleet angle for counterweight rigging is usually 1½ º.
Floor Block—Pulley mounted at the floor to hold a rope or cable in position. Sometimes called a Tension Block.
Floor Pocket—Electrical distribution device, mounted flush into the stage floor. May contain stage lighting receptacles, utility receptacles or sound or lighting control receptacles.
Fly Gallery—A catwalk above the stage floor from which counterweight and hemp (rope) rigging is operated.
Fly Loft—The space above the stage area that is not visible to the audience.
Fly In—The act of lowering a batten, curtain, drop, electric or set.
Fly Out—The act of raising a batten, curtain, drop, electric or set.
Fullness—Extra fabric that is added to a curtain to be sewn into pleats. 100 percent fullness means that the curtain would be double its finished width before the pleats are made.
G
Grid (Pipe)—An arrangement of pipes placed in two directions perpendicular to each other, often in a pattern of 4'x 4'squares. Typical in a television studio or black box theatre.
Gridiron (Grid)—An open floor, usually made above the stage area, from steel channels or grating, that is located near the roof steel. It provides mounting locations for rigging equipment and access to that equipment for inspection and maintenance.
Guide—Rollers or slides used to control the movement of rigging devices in tracks or on stretched cables.
H
Hand Line—A line, usually rope, that is pulled by hand to lift or control the movement of a load. Also known as a purchase line.
Head Block Beams—Structural steel designed to support the head blocks and carry vertical and horizontal loads. Aka, Head Well.
Head Block—Multiple sheave block mounted on the Head Block Beam above a counterweight arbor that changes the direction of lift and operating lines.
Hemp Rigging—A rigging system that employs ropes and sandbags instead of counterweight arbors or other devices. Usually used for temporary rigging.
House Left/Right—The sides of an auditorium as seen by an audience member while facing the stage.
House—General term for the large room where the audience is seated, regardless of the exact type of space (gymnasium, auditorium, church sanctuary, etc.). See "Auditorium."
I
Idler—A pulley designed to guide/support one or more cables from sagging and rubbing but not to make direction changes in the cable.
Incremental Block—A multi-grooved pulley that supports and changes the direction of cables between the load and the head block and that supports other, more distant, lines in the set.
Index Light—A lighting fixture containing a number of low-wattage lamps, mounted above the locking or pin rail.
Index Strip—A strip mounted on or near lock rail with cards, tape or other means to identify the individual rigging sets.
L
Lattice Track—A parallel pair of angles or other structural members that act as a track to guide an arbor or clew. Low friction slides or roller guides are placed on both sides of the device to be guided.
Lead (Lift) Line—Support line, running from the arbor, through head and loft blocks to one of several locations on rigging batten.
Leg Curtain—A curtain used to define the side limit of the stage and to mask or hide actors, lights, and unused scenery in the off stage area (wings).
Legs—In pairs, these are side masking curtains, and part of the cyc set.
Leno—Curtain fabric used primarily as a cyclorama fabric.
Lighting Bridge—A walkway across the stage where lights are hung and where they may be adjusted and maintained.
Line Shaft Winch—Winch with a series of cable drums connected to a gearbox by a common shaft used to lift and lower a load.
Live End—The end of a rope or part of a device that is active or load carrying.
Live Load—That part of a system load that may be added or deleted (i.e. Lights or scenery hung from a pipe batten).
Load Brake—A secondary brake that holds the full load in the system, usually in the case of a failure in the system.
Loading Gallery—A platform above the stage floor used to add or remove counterweights from the arbors. Usually located to allow access to the arbors when the battens are at their lowest positions. Sometimes called a Loading Bridge.
Lock Rail—A metal railing designed to support rope locks in a way that allows them to be safely operated. It carries modestly out of balance loads from the rigging system held by rope locks.
Loft Block—A pulley mounted to the gridiron or support steel, through which an individual lead line passes and turns down, going to the rigging batten or load.
M
Main Curtain—A curtain that is opened to signal the beginning of a performance. The Front Curtain is often used for this purpose.
Masking—A set of curtains or scenic elements used to define the visual limits of a performance area. Also known as a teaser or simply a border.
Mule Block—A pulley used to change the horizontal direction of a line.
Multi-Sheave Block—A block that contains a number of independent sheaves and bearings, usually on a common axle, so that each rope or cable can operate independently.
O
Off Stage—The stage area that is not a part of the acting area and is not visible to the audience.
Olio Curtain—A curtain located behind the "Front" or "Act" curtain and the "Rear" curtain. Used to close off a portion of the acting area for more intimate presentations. Common in older stages, although largely replaced by mid-stage traveler curtains in new facilities.
On Stage—The portion of the stage area visible to the audience, usually defined by masking curtains, scenery, an orchestra shell, or by lighting.
Orchestra Lift—A platform that is used to adjust the elevation of the musicians in relation to the stage and auditorium. Usually operates within the confines of an orchestra pit.
Orchestra Pit—An area between the stage and audience, usually depressed, where musicians sit, so the audience can hear the music and see the performance over the heads of the musicians.
Orchestra Shell—An enclosure on stage, consisting of walls and a ceiling that reflects sound into the auditorium.
Outrigger—A barrier device, usually built out from the side wall, that protects counterweight arbors from scenery, etc. that may be leaned against them. Can also be used to support the index lights.
Overspeed Brake—A secondary brake designed to halt a load if it exceeds a preset speed.
P
Pinrail—A rail to which hand lines are secured by tying around a belaying pin.. May also act as a safety railing at the edge of a gallery or walkway.
Pipe Clamp—Clamping device that bolts around a pipe for attachment of chain or cable hangers.
Pipe Grid—See "Grid".
Pitch Diameter—Diameter of a sheave or drum measured from the center line of the cable or rope to be wrapped around it.
Pivot Block—A pulley designed to adjust to structures at odd angles.
Pivoting Device—Rotating device, allowing a side leg to be turned on its vertical axis. Can be mounted to a batten or in a crosstrack.
Plug Box—Electrical distribution device, containing stage lighting circuit receptacles, either flush or on pigtails. Can be permanently mounted or attached to a flexible cable.
Portal—A portal consists of a header or border and legs that can be moved to adjust the size and shape of the proscenium opening to fit various performance needs.
Proscenium Arch—The opening in the proscenium wall through which the audience views a performance. Usually just called the proscenium.
Proscenium Legs—Curtains matching, or for use with, the front curtain, located on both sides in front of the proscenium arch. See also tormentors.
Proscenium Wall—The dividing wall or barrier between audience and the stage.
R
Raked Stage—A sloped platform that is lower near the audience for better visibility and higher at the rear, providing the illusion of distance. This is the source for the terms "Down Stage" and "Up Stage."
Rope Lock—A clamping device that prevents the hand line of an arbor from accidentally moving. Designed to hold the balanced load in a set at a fixed position.
S
Safety Chain—A secondary support line, usually of chain, that supports a fire curtain or other device should the primary support cable fail or become slack for any reason. The extra weight of fire curtain safety chains also helps the fire curtain accelerate at the start of its travel.
Sag Bar—A support rail, usually of wood or plastic, that keeps cables from sagging over a horizontal span due to their own weight. Sag bars don't carry any loads. Also see "Cable Roller."
Sandbag—A fabric bag that can be filled with sand and used for weighing down scenery supports. In rope rigging systems, a larger sandbag can be attached to the trim clamp to counterbalance the load hung from the set.
Scrim—A curtain made from a loosely woven special effects fabric that looks solid when lit from the audience side and becomes almost invisible when back lit.
Self-Climbing—A pipe grid or batten that has an integral device for raising and lowering.
Set—A system of cables, pulleys, lifting devices and battens that holds a specific set of scenic elements, curtains or lights.
Sheave—A wheel with a groove around its circumference to support and contain a rope or cable. Sometimes mistakenly called a pulley.
Single Purchase—A rope or cable passing from a lifting device over a block, or series of blocks, to a load is single purchased. Force must be exerted equal to the load to be held or raised.
Smoke Pocket—A metal pocket, usually installed on the proscenium wall, that supports a guide system at the edges of a fire safety curtain and helps prevent smoke passing around the edges of the curtain.
Spot Line—Any special-purpose single line, for either temporary or more permanent use.
Spotline Rigging—A temporary rigging system designed to be easily installed. Often rigged with rope instead of counterweight.
Stage Left / Right—The direction on stage, as perceived by an actor when facing the audience, to his left/right.
Stage Lift—A portion of the stage floor that may be raised or lowered by some type of mechanical lifting device.
Stage—The area where a performance is given.
Straight Lift Curtain—A curtain that can be raised (opened) without folding in any way.
Swivel Block—A pulley that moves or rotates around a fixed point.
T
Tab—A masking leg that is mounted at right angles to the front of the stage. Also see "Portal."
Tag Line—A line attached to a load to assist in controlling its movement.
T-Bar Wall—The wall made up of Tee Guides and the associated bracing.
Tee Guides—"T" shaped steel or aluminum members placed in parallel rows to guide arbors or clews. Guides may consist of low friction slides or rollers.
Tie-off Bracket—A bracket attached to rigging blocks, gridiron, or other structure to hold wires for guiding clews.
Tormentor Legs—Similar to proscenium legs, except located behind the arch. Sometimes refers to any masking curtains located at the sides.
Traction Drive Winch—Winch with a v-grooved drum that uses friction between cables and the sides of the grooves to engage the pulling cables. Increasing the cable tension causes the cables to jam tighter in the v-grooves.
Travel—The path of moving stage equipment and the distance moved.
Traveler Track—A horizontal guide used to support and operate a curtain, whether a front curtain, rear curtain or mid-stage traveler.
Traveler—A curtain operating on a horizontal track, that can be opened or closed to reveal or mask a portion of the stage.
Trim Chain—A length of chain placed between a lift line and a pipe batten or a batten and a scenic element to connect them and to facilitate minor height adjustment of the load.
Trim Clamp—Device fastened to the hand lines of a manual set to maintain an even trim.
Trim (a)—(1) A load is "in trim" when the equipment load equals the counterbalancing weight.(2) A set or element is trimmed when it has been placed in the desired position within the performance area.
Trim (b)—Adjusting a curtain, drop or other equipment so that it is the proper height and level.
Tripped—A curtain or scenic element is lifted by a second set of lines attached at the bottom or intermediate point on the piece causing it to store in half its normal height. Pulling the lines will cause the piece to fold in half or thirds. Note: If the piece is counterbalanced, the weight balance will shift as the piece is tripped.
U
Under Hung—Hung from the bottom of a beam or structure.
Under-hung Grid—Gridiron which has loft blocks mounted on the underside of the ceiling, over the grid.
Up Stage—The direction on stage referenced from the audience towards the back of the stage. See "Raked Stage."
Upright Grid—Gridiron that has loft blocks mounted on its upper side. Also called an overhung grid.
Upright—Resting on top of a beam or structure.
V
Valance—A special border behind the proscenium arch and in front of the front curtain. Usually is the same color and fabric as the front curtain.
Wall Batten—Horizontal structural members to which tee guide tracks are attached. Part of the tee wall.
Wall Knee—Bracket that attaches a wall batten to the building structure. Part of the tee wall.
Well—A reinforced open slot in the grid where the rigging equipment is mounted offering added strength.
Wings—The areas on either side of the stage, beyond the acting area.
Wire Grid—Sometimes called a "Tension Grid". It is formed of woven cables attached to, and supported by, a structural frame.
Wire Guide—Wires placed to control the location and travel of arbors, clews and curtains.
