Arc Lamp: A bulb that produces light by an arc created between two electrodes inside a glass envelope that contains a gas.
Aspect Ratio: The width of a picture or projection screen in relation to its height, usually expressed in a “width x height” manner, i.e., 4x3 or 4:3.
Audience Blinders (a.k.a. Molefays): A fixture that contains multiple bulbs (usually PARs) that is pointed at the audience and bumped for accents or used to illuminate the crowd.
Barn Doors: A unit that is mounted at the front of a lighting fixture with adjustable doors that shapes the beam and helps control spill.
Barrel: The part of an ellipsoidal fixture that contains the lenses.
Batten: Metal pipes suspended in rows above a stage, used for the rigging of lighting and scenery.
Black Burst: A blank video signal that synchronizes video sources so they’re moving in step from one frame to the next.
Bump: A quick level change in lighting, usually to full.
Coffin Locks (a.k.a. Roto-Lock): A mortised connector used to couple stage platforms or scenic items together.
Color Temperature: The measurement in degrees on the Kelvin scale indicating the hue of a specific type of light source.
Component Video: An analog video signal using three conductors, one each for luminance (with sync and green reference), blue minus luminance and red minus luminance.
Composite Video: A single-channel analog video signal carrying all information.
Cyc Light: A wash fixture normally used in multiples to light up a cyclorama, or now more commonly any backdrop.
Cyclorama: A curved wall or curtain at the back (upstage) of a theater stage.
Dichroic: A glass filter that allows a limited range of color to pass through a light fixture while reflecting the other colors in the spectrum.
DMX512: The standard digital lighting protocol that can send 512 channels of control information to dimmers, automated lighting fixtures or special effects.
Dress Kit: Drapery surrounding a portable projection screen, helping control spill light and giving a finished appearance.
Ellipsoid Reflector Spotlight (a.k.a., Ellipsoidal, ERS, Profile or Leko): A spot stage lighting fixture with an ellipsoid shaped reflector that directs light through the barrel and lens, allowing focusing of the beam.
Footcandle (fc): A unit of measurement of illumination – one footcandle equals one lumen per square foot.
Gel: Common name for a color lighting filter.
Genlock: Synchronization of the video signals of multiple devices to a single source, like a black burst generator.
Gobo (a.k.a. Pattern): A glass or metal plate with a design etched or imprinted on its surface that can be projected when inserted into the pattern slot of an ERS type fixture.
Intelligent Light (a.k.a. Intel or Automated Light): A lighting fixture that can be controlled from a console that can pan, tilt, color or shape the light beam.