- A
- Accent Lighting
Lighting that emphasizes a particular object or draws attention to a particular area for aesthetic purposes.
- Ambient Lighting
General lighting diffused within an entire room, not focused on any specific area. Essential for creating an overall mood or atmosphere in a space.
- Ambient Temperature
The temperature of the air surrounding lighting equipment, important for evaluating the thermal performance of light sources.
- Ampere
The unit of electric current. Important for calculating the load a lighting circuit can safely handle. Symbol: A, often shortened to 'AMP'
- Anode
The positive pole or electrode of an electrolytic system, such as a fluorescent lamp, where electrons flow into the device.
- ANSI
American National Standards Institute. Oversees the creation and dissemination of norms and standards within the United States, including those for lighting products.
- Anti-Glare
Refers to devices or techniques used to prevent or minimize glare from light sources.
- Architectural Lighting
Lighting that is integral to the design of a building, including both natural and artificial light sources.
- B
- Backlight
Lighting that comes from behind the subject, often used to create a silhouette effect or to separate the subject from the background.
- Ballast
A device used to regulate the current in fluorescent or HID lighting systems, ensuring the proper startup and operation of the light source.
- Ballast Factor (BF)
Describes how the ballast influences the light output of the lamp it powers, compared to the lamp's rated output.
- Beam Angle
The angle at which light is distributed or emitted from a light source, determining how spread out the light will be.
- Bi-Level Lighting
Systems with two levels of light output (high/low), often used for energy savings during periods of lower activity.
- Black Body
An idealized physical body that absorbs all incident electromagnetic radiation, used as a reference in color temperature measurement.
- Brightness
The perception elicited by the luminance of an object, often confused with luminance, which is a measurable attribute.
- Bulb
A common term used to refer to the light-producing component of a lamp.
- C
- Candela (cd)
The SI unit of luminous intensity, describing the amount of light emitted in a particular direction.
- Candlepower
An older term for luminous intensity; now largely replaced by the candela.
- Cathode
The negative pole or electrode of an electrolytic system, such as a fluorescent lamp, where electrons flow into the device.
- CCT (Correlated Color Temperature)
Describes the color appearance of the light emitted by a lamp, relating its color to the color of light from a reference source when heated to a particular temperature, measured in Kelvin (K).
- Chandelier
A decorative hanging light with branches for several light bulbs or candles, often used in elegant settings.
- Circuit
A complete path through which electricity flows from the power source, through the lighting device, and back to the source.
- Color Rendering Index (CRI)
A measure of the ability of a light source to accurately reproduce the colors of various objects in comparison with a natural light source.
- Color Temperature
The temperature of an ideal black-body radiator that radiates light of a comparable color to that of the light source, measured in Kelvin (K). Indicates whether the light is a warm, neutral, or cool shade off white.
- Compact Fluorescent Lamp (CFL)
A type of fluorescent lamp that uses a compact electronic ballast in the base of the lamp, offering a compact alternative to traditional fluorescent tubes.
- D
- DALI (Digital Addressable Lighting Interface)
A protocol for digital communication between lighting control devices, allowing for more complex and flexible lighting systems.
- Daylighting
The practice of placing windows or other openings and reflective surfaces so that during the day natural light provides effective internal lighting.
- Diffuser
A device that spreads the light from a light source evenly to reduce glare and soften the light.
- Dimmer
A device used to lower the brightness of a light. By changing the voltage waveform applied to the lamp, it is possible to lower the intensity of the light output.
- Direct Lighting
Lighting that shines directly from the light source to the area being illuminated, without being diffused by intervening materials or surfaces.
- Directional Lighting
Designed to be directed or focused to a specific area, often used to highlight artwork or architectural features.
- E
- Efficacy
The efficiency of a light source measured in lumens per watt (lm/W). It indicates the amount of light produced per unit of power consumed.
- Egress Lighting
Lighting specifically designed to illuminate paths of exit in case of an emergency.
- Electroluminescent (EL)
Describes materials that emit light in response to an electric current or a strong electric field.
- Emergency Lighting
Lighting designed to automatically come on when the power supply to the normal lighting fails.
- F
- Floodlight
A broad-beamed, high-intensity artificial light used to illuminate outdoor areas or large spaces.
- Fluorescent Lighting
A type of lighting that uses electricity to excite mercury vapor in argon or neon gas, resulting in a fluorescent glow. Efficient for widespread lighting.
- Foot-Candle
A non-SI unit of illuminance, representing the illuminance on a surface that is one foot away from a single candle. Equivalent to approximately 10.764 lux.
- G
- Glare
The discomfort or impairment of vision experienced when parts of the visual field are much brighter than the average brightness to which the eyes are adapted.
- Goniophotometer
An instrument used to measure the light emitted from a source at different angles, used in the development and testing of lighting fixtures.
- H
- Halogen Lamp
A type of incandescent lamp that contains a small amount of halogen such as iodine or bromine, which increases the life and efficiency of the lamp.
- Harmonic Distortion
A distortion in the electrical waveform supplied to the lighting fixture, often caused by electronic lighting controls or power supplies, which can affect the performance of lighting equipment.
- High-Intensity Discharge (HID) Lamp
A type of electrical gas-discharge lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube.
- I
- Illuminance
The total luminous flux incident on a surface, per unit area. It is measured in lux (lx).
- Illuminance Meter
A device used to measure the amount of light falling on a surface, usually in lux or foot-candles.
- Incandescent Lighting
Lighting produced by heating a filament within a bulb until it glows. Known for warm, inviting light but is less energy-efficient than other forms of lighting.
- Indirect Lighting
Lighting where the light emitted from a source is reflected off ceilings, walls, or other surfaces before reaching the target area, reducing glare and creating a uniform light distribution.
- J
- Joule
A unit of energy in the International System of Units. In lighting, it's used to measure the energy consumed by light sources.
- K
- Kelvin (K)
A unit of measure for the color temperature of light sources. Lower Kelvin numbers mean the light appears more yellow; higher Kelvin numbers mean the light is whiter or bluer.
- Key Light
The primary source of light in a lighting scheme, especially in photography or cinematography, usually placed to highlight the form and dimension of the subject.
- L
- Lamp Life
The average expected lifetime of a lamp, typically given in hours, before it fails or its light output decreases significantly.
- Lamp Lumen Depreciation (LLD)
A measure of how much the light output of a lamp decreases over time.
- LED (Light Emitting Diode)
A semiconductor device that emits light when an electric current passes through it. Known for its efficiency and longevity.
- Light Pollution
Unwanted or excessive artificial light that can have harmful effects on human health, wildlife, and the ability to observe stars in the night sky.
- Lumen (lm)
A measure of the total quantity of visible light emitted by a source.
- Lux (lx)
The SI unit of illuminance, equal to one lumen per square meter. It measures the amount of light that falls on a surface.
- M
- Mood Lighting
Lighting designed to create a specific emotional atmosphere or feeling in a space.
- Mounting Height
The height at which a lighting fixture is installed from the floor, affecting the spread and intensity of the light.
- N
- Natural Light
Light from the sun. In lighting design, it's considered for its quality, availability, and how it interacts with architectural spaces and materials to improve illumination and energy efficiency.
- NEMA
NEMA (National Electrical Manufacturers Association) – An organization that develops standards for electrical equipment, including lighting fixtures.
- O
- Occupancy Sensor
A device that detects the presence of people within a space and turns lights on or off accordingly, improving energy efficiency.
- Optics
The components of a lighting fixture that control the distribution of the light emitted, including lenses, reflectors, and diffusers.
- P
- Pendant Light
A light fixture that hangs from the ceiling via a cord, chain, or metal rod, often used for task lighting or accent lighting over tables or counters.
- Photobiology
The study of the effects of light on living organisms, important in designing lighting that does not harm human health or the environment.
- Photometrics
The study of light and luminous intensity, including measurements of illumination, luminance, and color properties of light sources and spaces.
- Q
- Quality of Light
A subjective measure that encompasses various aspects of the light produced by a source, including color temperature, color rendering, and absence of flicker.
- R
- Recessed Lighting
Lighting fixtures installed into an opening in the ceiling, providing a clean, streamlined look by hiding the fixture within the ceiling except for the light itself.
- Reflector
A component of a light fixture that redirects the light from the lamp to increase efficiency and direct the light where it is needed.
- Retrofit
The process of upgrading existing lighting fixtures or systems with new components, often for the purpose of improving energy efficiency or performance.
- S
- Sconce
A type of wall-mounted fixture that provides indirect lighting, often used for ambient lighting in corridors or as accent lighting for decorative purposes.
- Smart Lighting
Advanced lighting technology that can be controlled remotely through devices such as smartphones or voice-activated home automation systems, allowing for adjustments in brightness, color temperature, and scheduling.
- Strobe Lighting
A type of lighting that produces short, intense bursts of light, commonly used in photography, entertainment, and safety signaling.
- T
- Task Lighting
Lighting aimed at a specific area to provide illumination for the performance of visual tasks.
- Task Luminaire
A lighting fixture designed specifically to provide light for a particular task, such as reading or cooking.
- Track Lighting
A lighting system where fixtures are attached anywhere on a continuous track device which contains electrical conductors. Particularly useful for directing light at various angles and locations.
- U
- Uniformity Ratio
The ratio of the minimum to the average illuminance across a given area, indicating how evenly light is distributed
- Uplighting
Lighting that is directed upwards to highlight architectural features, create a sense of space, or provide indirect ambient lighting.
- V
- Visual Comfort Probability (VCP)
A metric that predicts the proportion of people who will find a given lighting environment comfortable in terms of glare.
- Voltage
A measure of electrical potential, with most lighting designed to operate at a specific voltage for safety and efficiency.
- W
- Wall Washing
A lighting technique used to evenly illuminate a wall surface, minimizing shadows and highlights to draw attention to the wall itself.
- Watt (W)
The unit of power. In lighting, it is used to measure the energy consumption of light sources.
- X
- Xenon Arc Lamp
A specialized type of gas discharge lamp that produces light by passing electricity through xenon gas, known for its bright, white light and high color rendering. A type of gas discharge lamp, which uses xenon gas to producea bright white light. Known for high color rendering and being used in applications from automotive headlights to projectors
- Y
- Yield
In lighting, this refers to the efficiency with which a lighting system converts electrical energy into visible light, considering all losses due to heat, reflection, and diffusion.
- Yoke
A bracket or support structure that allows a light fixture to be mounted and possibly to be aimed or adjusted.
- Z
- Zone Control
Dividing a space into lighting zones for the purpose of creating different atmospheres or functional areas, often controlled separately to match the desired mood or activity in each zone.
