Act Curtain

Curtain closest to the proscenium arch. 

Amp (A)

An abridged version of Ampere.

Amperage (A)

The measure of electrical current in Amperes.

Ampere (A)

A unit of measure for electrical current.


Abbreviation for Analog Multiplex.

Analog Multiplex (AMX)

An older control signal for theatrical dimming systems.


Abbreviation for American National Standards Institute.


A three letter system developed to similar lamps by different manufacturers.  The individual letters do not represent anything specifically.


Area of the stage in front of the proscenium arch.


Device that holds the counterweight.  This piece of equipment is usually guided with either wire or track, and operates vertically on one of the stage walls.


A light caused by electricity jumping from one point to another through open air.

Austrian Drape

Normally an Act Curtain, with the fullness sewn in vertically, creating a scalloped effect across the curtain when its in the full down position.  At each of the vertical seams there are lift lines for raising the curtain.

Automated Light

A fixture which has motorized, remote controllable attributes, such as color changing, beam shape, or gobo rotation.


A term used to describe a light which has its lamp in the same plane as the optical system.

Back Light

A light placed behind (Upstage) of the subject.  Often used to make the subject stand out from the background.


A device which limits electrical current to an arc or florescent source fixture.

Bare Ends

Leads without a connector installed.

Barn Door

Adjustable flaps which limit the beam from a fixture.


A metal piece used as a foot to stand items up.

Base weight

The amount of counterweight needed in an arbor to balance the permanent load on a line set.


The pipe that runs across the stage to which is attached scenery or curtains or such.  The batten is attached to the counterweight arbor by the running lines

Bi-Part Drapery

A Curtain that splits in the middle  Usually it is operated by handline from one side of the stage.


Rigging term for a pulley.


Curtains which run across the stage used to mask the area above the stage proper. There is usually more than one of these curtains and they are referred to numerically by their position moving upstage, away from the audience.


A catwalk usually adjustable in height located above the stage proper used for hanging lights.

Cable clips

Also called Crosbys (brand name)  this is a device used to temporarily attach two pieces of cable together.


Steel or wood structure for accessing areas above stage and house.


A device for attaching multiple lines to a single haul line.

Contour Curtains

Similar to an Austrian Drape because it uses vertical lift lines, however the fullness is sewn in horizontally.  When the drape is down it appears to be a very full conventional drape.


Bricks, usually steel or iron with notches, which are loaded into the arbor and used to balance the load on a batten.

Counterweight Arbor 

The device that holds the counterweight.  See Arbor.

Crash Rail

Usually a wood block running the length of the Lock Rail and mirrored at the head blocks to stop batten travel at the maximum in and out elevation.


A lighting fixture which produces an even wash on a flat surface, also called a wall wash in Architectural lighting.


(Cyc) A curtain sewn flat usually muslin and either blue or white which is used upstage to give perception of the sky in the background.

Dash pot

A device use to control the speed of the descent of the fire curtain for the  last eight feet.

Double Purchase

A system which uses mechanical advantage to either increase the distance items can fly or the weight a system can lift.

Dead Hung

Items that are hung above the stage and not intended to move


Downstage is closest to the audience --- Upstage furthest away from the audience.


Entertainment Service and Technology Association trade association for manufacturers, distributors and users of theater technology.  Charged with creating the ANSI standards for theatre.

Ellipsoidal Reflector Spotlight

Common theatrical lighting fixture that can produce a hard edged beam, allowing for image projection and clean shutter cuts.

Fire Curtain

A nonflammable curtain immediately behind the proscenium contained in the smoke pocket.  A safety device used to protect the audience from possible smoke or fire originating from the stage area.


The act of moving items up and down.

Fly Loft

The area above the stage where all the blocks and pulleys are located, used for the storage of scenery and equipment.


A wash light utilizing a stepped lens and a adjustable base position.


A curtain, which runs the width of the stage and is the height of the proscenium that is raised and lowered to mask items.

Grid (Grid Iron)

The structure and level at which loft blocks are placed

Hand Line

(also called operating line) This is the rope that passes through the rope lock around a floating tension pulley and is attached to the top and bottom of the counterweight arbor.  Moving  this line up or down causes the arbor to move which then causes the batten to move.

Head Beam

The large I-Beam(s) which holds the head blocks.

Head Block

A large multi grooved pulley over which the hand line and lift lines turn.  Usually located above the arbor.

Heavy In 

Not enough counterweights in the arbor. (Out of balance condition)

Heavy Out 

Too many counterweights in the arbor. (Out of balance condition)

Hemp System

A method of rigging which utilizes manila rope or synthetic hand line and sandbags.

"J" Bar

A different metal shape that is beginning to replace "T" Bar.


Long, tall, narrow curtains used to mask the side of the stage.  Usually these curtains are pairs hanging on the same line set.  The number of legs is dependent upon the depth of the stage and the width of auditorium.

Lift Line

The cable or rope that attaches to the batten and arbor.

Line Shaft

Type of motorized winch that allows one motor to run multiple cable drums.

Loading Gallery

A platform or catwalk attached to the side walls of the stage house to allow loading and unloading of the arbor when the batten is at its "in" trim.

Loft Block

A single groove pulley for the individual working line.

Lock Rail 

A structural element of the fly system, usually located on the stage floor and directly attached to the building structure.  Attached to this unit are all the rope locks, tension blocks, and line set identification tags.

Loft Well

The space between I-Beams in which the lift lines run.


(Act, Grand, Front, etc.)  This curtain is the first curtain on the stage and generally goes floor to slightly above the proscenium arch and is opened and closed to reveal the production.

Motorized Rigging

Lifting systems that use either a winch or motors to lift items above a stage.


To properly wire shackles and turn buckles so they can not undo themselves.  Usually accomplished by running a piece of rebar wire through the eyes.

Mule Block

A pulley that changes the direction of the lift lines.

Nico Sleeve

A copper sleeve when compressed (swaged) over two pieces of the same diameter cable holds them together permanently.  This is the preferred  industry practice.


The area toward the wall of the stage.


The area toward the center of the stage

Pipe Weight

The amount of counterweights needed to keep an empty batten evenly balanced.

Pin Rail

A component of a hemp system consisting of a pipe or wood rail with pegs in it to tie off lift lines.

Plaster Line

An imaginary line running across stage on the upstage side of the proscenium wall.


The picture window that frames the stage.


Common term for stage drapery.


A general term used to describe all systems used to support, move or fly scenery, lighting fixtures, drapery and other masking devices.

Rope Locks

A device designed to hold a balanced counterweight load at a particular elevation.  A Rope lock will not hold an unbalanced load or stop a run-a-way.


Theater jargon which indicates an out of balance batten that is out of control.  A run-a-way can happen very fast and you should not try to stop it.  If a set is running you should yell "HEADS UP" and get away.

Running line 

(also called working line, or lift line, or load line) This is usually 1/4" 7x19 aircraft cable.  It can also be 3/16" or sometimes larger.  The diameter of the cable is determined by the safe working load designed into the system.


A curtain that when lit from the front appears opaque but when lit from the rear allows items to be seen.


A unit of rigging consisting of the batten and all other support cables, blocks and mountings.

Sheave (shiv)

The grooved wheel in a pulley that a cable rolls on.

Single Purchase

A method of lifting items where an equal load is located onstage and offstage to create a balanced system.

Snub Line 

A short piece of rope used to tie down a moving component of the system.

Spreader Plates

Flat plates that ride between the bars in an arbor to keep the counterweight captured between the arbor rods, particularly in the event of a run-a-way.


The actors left when facing the audience.


The actors right when facing the audience.


The rails which guide the counter weight arbor as it moves up and down.  Sometimes referred to as the tee bar battery.


Masking curtains which run perpendicular to the proscenium opening.

Tension Block

(Welsh block, floor block) The bottom pulley which turns the hand line from the rope lock back up to the head block.


A rounded item that gives the proper curve for terminating wire rope.


Usually located immediately up or down stage of the Act Curtain these are used to narrow the proscenium opening.

Trim Chain 

A short piece of passing link chain permanently attached to the running line and wrapped around the batten (traditionally 1-1/2 times) and then attached back to itself.  This chain should be 4/0 passing link chain about 30" in length.


Downstage is closest to the audience --- Upstage furthest away from the audience.

Walk Draw

Drapery which is pulled by hand rather than with a pulley system.


A manual or power-operated device used to wind cable to raise or lower items


The curtain used to mask across the stage.  This curtain usually matches the color of the main.

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