AC (Alternating Current) – Current that flows in one direction and then alternates its flow in the other direction.

Accent Lighting – Directional lighting, recessed down light, that draws attention to a displayed object or surface, or to highlight, dramatize, and focus attention on a defined space.

American Lighting Association (ALA) – The trade organization of the residential lighting industry in the U.S., Canada and the Caribbean, with members that are lighting manufacturers, showrooms, independent manufacturers’ sales representatives, designers and other industry associates who promote the sale and proper use of quality lighting products in the home.

Ambient Lighting – General lighting for any interior or exterior environments, in contrast to directional lighting.

Amperes (Amps) – A measure or intensity of electrical current. In incandescent lamps, the current is related to voltage and power as follows: Watts (power) = Volts x Amps (current).

Anodized – A highly durable finish consisting of a thin, near transparent coating of aluminum oxide on the surface of an aluminum reflector.

American National Standards Institute (ANSI) – A consensus-based organization which coordinates voluntary standards for the physical, electrical and performance characteristics of lamps, ballasts, luminaires and other lighting and electrical equipment.

Antique Finish – A finish that simulates aging, often accompanied with a dark pigment paint wiped across a metal part.

Back Light – Illumination from behind an object that creates a silhouette or a dramatic outline, creating separation between the subject and its background.

Baffle – Fixture component, an opaque or translucent element that blocks light to prevent glare and control brightness, or to reflect and redirect light.

Base or Socket – The socket is the receptacle connected to the electrical supply; the base is the end of the lamp that fits into the socket.

Bayonet – A style of bulb base, which uses keyways instead of threads to connect the bulb to the fixture base. The bulb is locked in place by pushing it down and turning it clockwise.

Beam – The key element of a directional light, accent light, or down light.

Beam Angle – The angle between the two directions for which the intensity is 50% of the maximum intensity in a plane through the nominal beam centerline.

Beam Spread – Width of the beam in degrees, defined as the point where intensity falls to 50% of maximum candlepower. For most PAR and MR lamps, this is the apex angle. For asymmetrical beams, this is expressed as length x width. Most reflector halogen bulbs are offered in varying degrees.

Beveled Glass – Clear glass with edges cut to add depth and a special effect.

Binning – A process by which LEDs are sorted in order to maintain proper color consistency between individual LEDs.

Bullet – An accent light, sometimes with a round back, used to create dramatic light in a small space.

Bi-Pin – Any base with two metal pins for electrical contact, including a variety of halogen lamps.

Bulb – Bulb refers to a lamp or the outer glass bulb containing the light source.

Canadian Standards Association (CSA) – An organization that writes standards and tests lighting equipment for performance, as well as electrical and fire safety. Canadian provincial laws generally require that all consumer products in Canada must have CSA or equivalent approval.

Candela (cd) – The measure of luminous intensity of a source in a given direction, a term retained from the early days when a standard candle of a fixed size and composition was defined as producing one candela in every direction. The SI unit of luminous intensity, equal to one lumen per steradian.

Candlepower – Luminous intensity expressed in candelas, in a particular direction.

Canopy – Fixture part that covers an outlet box, attachment point or the decorative piece used to cover the electrical wires and mounting hardware.

Center Beam Candlepower (CBCP) – The luminous intensity at the center of the beam, measured in candelas.

Centigrade – Celsius temperature scale where 0°C = 32°F.

Circuit Breaker – Protecting device in the electrical panel that disrupts the electrical path if overloaded.

Circuit – Wiring path for electricity.

Chip –A termed used for the board or “light engine” to which the LEDs are applied. The chip or “light engine” is a circuitry board for the LED.

Color Rendering Index (CRI) – An international system used to rate a lamp’s ability to render objects’ colors (color rendition). The higher the CRI (based upon a 0-100 scale) the richer colors appear. CRI ratings may be compared, but a numerical comparison is only valid if the lamps are close in color temperature.

Color Temperature (Correlated Color Temperature – CCT) – A number indicating the degree of “yellowness” or “blueness” of a white light source. Measured in Kelvin, yellowish-white (warm) sources, like incandescent lamps, have lower color temperatures in the 2700K-3000K range; white and bluish-white (cool) sources, such as cool white (4100K) and natural daylight (6000K), have higher color temperatures.

Contrast – The ratio of the luminance of an object to that of its immediate background.

Controller – A device that controls the output of color-changing and tunable white lighting fixtures with software for lighting design and hardware components for sending control data to fixtures.

Cool White (CW) – A lamp’s color temperature of approximately 4100 K.

Current Type (AC/DC) – Operational voltage based on either Alternating Current or Direct Current.

Cutoff Angle – The critical viewing angle beyond which a source can no longer be seen because of an obstruction (such as a baffle or overhang). The angle, measured up from nadir, between the vertical axis and the first line of sight at which the bare source is not available.

Die-cast – A term that refers to the process of forcing molten metal, under great pressure, into a die or form to give it a specific shape. A very efficient process, excess material can be reused for future casting.

Diffusers – Those surfaces and glazing materials that redistribute some of the incident flux by scattering light in different directions.

Dimmable – The variation of lumen output while maintaining reliable performance.

Dimmer, Dimming Control – A device used to control the intensity of light emitted by a luminaire by controlling the voltage or current available to it, reducing the wattage, saving energy and changing the effects.

Diodes – Semiconductors similar to a computer chip that emit light when electricity is applied to them.

Direct Lighting – Lighting that involves luminaires that distribute 90 to 100 % of the emitted light in the general direction of the surface or object to be illuminated, usually in a downward direction.

Down Light – Small direct lighting unit that directs light downward and can be recessed, surface mounted, or suspended

Efficacy – The effectiveness of a light source to convert electrical energy to lumens of visible light. A measure of the luminous efficiency of a radiant flux, expressed in lumens per watt as the quotient of the total luminous flux by the total radiant flux. For electric sources, this is the quotient of the total luminous flux emitted by the total lamp power input.

Efficiency – The efficiency of a light source is simply the fraction of electrical energy converted to light or the percentage of the lamp lumens that actually comes out of the fixture.

Energy Star – A United States government program created in 1992 by the US Environmental Protection Agency in an attempt to reduce energy consumption and greenhouse gases. What began, as a voluntary labeling program has grown into one of the largest efforts worldwide to promote energy efficient consumer products.

Energy Policy Act (EPACT) – Comprehensive 1992 energy legislation passed by the U. S. Congress that includes lamp labeling and minimum energy efficacy (lumens/watt) requirements for many incandescent and fluorescent lamps.

Flux – The measurement of the light intensity produced by a lighting fixture. The rate of the flow of light per unit of time expressed in lumens per square meter.

Flood Spread – Beam pattern of a reflector lamp, which disperses the light over a wide beam angle, typically 20-60 degrees, with Narrow Flood to Wide Flood designations.

Foot Candle – A standard measurement of illuminance or light falling on a surface, representing the amount of illuminance on a surface one-foot square on which there is a uniformly distributed flux of one lumen. One footcandle is equal to one lumen per square foot and one foot in distance from the light source.

Fully Rated Life – The end of the life of an LED is determined by the point at which the LED fails to deliver at least 70% of initial lumen output.

Fuse – A type of low resistance resistor that acts as a sacrificial device to provide over current protection, of either the load or source circuit.

General Lighting – Lighting designed to provide a substantially uniformed illuminance throughout an area.

Glare – Visual discomfort or loss in visual performance and visibility caused by excessive brightness.

Halogen Lamp – A halogen lamp is an incandescent lamp with a filament that is surrounded by halogen gases that allow the filaments to operate at higher temperatures and higher efficacies, and prolonging lamp life. Produces crisp white light.

Heat Sink – A section of the thermal system that conducts or convects heat away from LEDs, extending lamp life.

IALD – International Association of Lighting Designers

IES – Illuminating Engineering Society

Illuminance – The density of incident luminous flux on a surface or plane; illuminance is the standard metric for lighting levels, and is measured in lux (lx) or footcandles (fc). It is also called light level (lumens/m2 =lux), the intensity or degree to which something is illuminated (it is not the amount of light produced by the light source).

Illumination – An alternative term for illuminance and frequently used to designate the act of illuminating or lighting a space.

Incandescent Lamp – Typical a halogen light bulb that generates light utilizing a thin filament wire heated to white heat by an electric current passing through it.

Indirect Lighting – The lighting of a space (such as a cove) by directing the light from luminaires upwards towards the ceiling or wall using an inconspicuous light source.

Input Voltage – Power supply voltage required for proper operation of fluorescent, transformers, HID ballast or LED drivers.

Kelvin – A unit of measurement for color temperature of a light source, ranging from warm white in the 2700K-3000K range; cool white (4100K) and natural daylight (6000K).

Kilowatt (kW) – The measure of electrical power equal to 1000 watts.

Kilowatt Hour (kWh) – The standard measure of electrical energy and the typical billing unit used by electrical utilities for electricity use. A 100-watt lamp operated for 10 hours consumes 1000 watt-hours (100 x 10) or one kilowatt-hour. If the utility charges $.10/kWh, then the electricity cost for the 10 hours of operation would be 10 cents (1 x $.10)

Lamp – An electrically energized source of light, commonly called a bulb or tube. The complete light source package, including the inner parts as well as the outer bulb or tube. Also refers to a portable luminaire.

Lamp Watts – Input power used to operate lamps.

LED – A Light Emitting Diode or an electronic semi-conductor device that emits light when an electric current passes through it.

LED Driver – An electronic circuit that converts input power into a current source and protects LEDs from normal voltage fluctuations, over-voltages, and voltage spikes.

LED Luminaire – A type of solid-state lighting (SSL) that uses light-emitting diodes (LEDs) as the source, optics to distribute the light, an electronic driver to control the electrical current, and thermal management to protect the LEDs.

LED Light Engine – An integrated assembly comprised of LEDs or LED arrays, LED driver, and other optical, thermal, mechanical, and electrical components.

LED Module – A single LED device or group of self-contained LED devices designed either to function on their own or to plug into a compatible LED fixture.

Lens – A transparent or semi-transparent glass or synthetic element, which controls the distribution of light by redirecting individual rays. Luminaires often have lenses in addition to reflectors.

Light – Radiant energy that is capable of exciting the retina and producing a visual sensation, sometimes designated as light.

Louver – Series of baffles used to shield a source from view at certain angles, to absorb, block, reflect or redirect light.

Low-Voltage LED – LED that uses low-voltage power distribution to each luminaire.

Lumen – A lumen is a unit of standard measurement used to describe how much light is contained in a certain area. The lumen is part of a group of standard measurements known as the photometry group, which measures different aspects of light.

Lumen Depreciation – The decrease of lumen output over time, caused by bulb wall blackening, phosphor exhaustion, filament depreciation and other factors.

Luminaire – A complete lighting unit consisting of a lamp (or lamps), ballast (or ballasts) as required together with the parts designed to distribute the light, position and protect the lamps and connect them to the power supply. A luminaire is often referred to as a lighting fixture.

Luminance – A measure of “surface brightness” when an observer is looking in the direction of the surface.

Lux (lx) – The unit of illuminance equal to one lumen per square meter.

Mercury Lamp – A high-intensity discharge light source operating at a relatively high pressure and temperature in which most of the light is produced by radiation from excited mercury vapor.

Metal Halide Lamp – A high intensity discharge light source in which the light is produced by the radiation from mercury, plus halides of metals.

MR-16 and MR-11 – Low voltage compact reflector halogen lamps used for accent and spot lighting.

National Electric Code (NEC) – A nationally accepted electrical installation code to reduce the risk of fire, developed by the National Fire Protection Association.
Organic Light-emitting Diodes (OLED) – Organic light-emitting diodes (OLEDs) are based on organic (carbon based) materials. In contrast to LEDs, which are small point sources, OLEDs are thin films of small organic molecules in a crystalline phase, or a flexible polymer, that create light with the application of electricity. OLEDs are still being developed as a practical illumination source.
Photometry (Photometrics) – The measurement of a fixture’s or lamp’s optics including luminance, luminous flux, luminous intensity, and spectral distribution of visible light.
Reflectance – The ratio of light reflected by a surface to the total amount of radiation incident on the surface.

Reflector – Device used to redirect the flux from a source by the process of reflection.

Responsible Lighting – A company’s holistic approach to business, encompassing a deep commitment to responsible eco-friendly manufacturing, extensive research/development, energy saving technology, and altruism.

Retrofit – the retrofit LED is a bulb or trim that is designed to convert an existing line voltage luminaire housing to an energy efficient LED luminaire.

Shade – Screen made of opaque or diffusing material designed to prevent a light source being directly visible at normal angles of view.

Semiconductor – A material that has an electrical conductivity between that of a conductor and an insulator. Devices made from semi-conductor materials are the foundation of modern electronics.

Solid State Lighting (SSL) – A type of lighting that uses semiconductor light-emitting diodes (LEDs), organic light-emitting diodes (OLED), or polymer light-emitting diodes (PLED) as sources of illumination rather than electrical filaments, plasma (used in arc lamps such as fluorescent lamps), or gas. The term “solid state” refers commonly to light emitted by solid-state electroluminescence, which creates visible light with reduced heat generation or energy dissipation.

Spot – A luminaire or lamp with a tight beam of light, typically around 10 degrees or less. It comes from the fact that such a lamp produces a narrow spot of light as opposed to a wide flood of light.

UL Listing – UL stands for Underwriters Laboratory. It is a trusted resource across the globe for product safety certification and compliance solutions.

Underwriters’ Laboratories (UL) – A private organization which tests and lists electrical and lighting equipment for electrical and fire safety according to recognized industry standards.

Volt – A measurement of the electromotive force in an electrical circuit or device expressed in volts.

Voltage – A measure of “electrical pressure” between two points, voltage is the difference in electric potential between those two points.

Warm White Light (2700K-3000K) – A yellowish light that helps enrich the warm colors in your home and are suitable for lounges, hallways, bedrooms and other areas where people relax.

Watt – The unit of electrical power used to indicate power consumption, as used by an electrical device during its operation.