Lighting Terms

Lighting terms to assist with purchasing light fixtures from Specialty Lighting.  Contact a representative for assistance.

accent lighting

Provides directional lighting to accent or draw attention to an object or an area within a space.

ambient lighting

Provides a substantially uniform light level throughout an area and also referred to as general lighting.


A device that is used with a fluorescent or high-intensity discharge (HID) lamp to provide the necessary circuit conditions (voltage, current, and wave form) for starting and operating the lamp.


Refers to the end of a light source or lamp which connects into a socket on a fixture.  There are two main types of lamp (light bulb) bases: screw bases and pin bases.

beam angle

The beam angle of a lamp is the angle at which the light is distributed or emitted.   The beam angle defines the area where the lamp radiates at least half (50%) of its maximum luminous intensity.  The full luminous intensity (100%) is only achieved exactly in the center of the light circle.

candela (cd)

The candela is the SI (International System of Units) base unit for luminous intensity. The candela (cd) is used to measure the brightness of light sources.

can lights

Round recessed downlight luminaires.  Also,  surface-mounted luminaires, usually a downlight, that has a cylindrical shape.  Sometimes called “high-hats.”

color rendering index (CRI)

Color rendering index (CRI) measures how a light source shows colors “naturally” when compared to either incandescent light or daylight.  The color rendering index (CRI) is measured as a number between 0 and 100.  At zero (0), all colors look the same.  A CRI of 100 shows the true colors of the object.  Incandescent and halogen light sources have a CRI of 100.  Typically, light sources with a CRI of 80 to 90 are regarded as good and those with a CRI of 90+ are excellent.  The general rule is:  The higher the CRI, the better the color rendering capacity.

compact fluorescent light (CFL)

A smaller or more compact version of a fluorescent tube.  CFLs are available with both screw-in and pin-bases along with a wide range of light temperatures and sizes.

correlated color temperature (CCT)

Correlated color temperature refers to the warmth (amber) or coolness (blue) of a light source and is measured in degrees of Kelvin (K) on a scale from 1000K to 10,000K.  Generally, warm white light is anything 2000K-3000K, daylight or cool white ranges from 4100K-6500K. 3000K to 3500K, a middle ground often called neutral, can look either cool or warm depending on the furnishings nearby.


A device to redirect or scatter the light from a source, primarily by the process of diffuse transmission.  Diffusers reduce glare and also soften light emitted from a light source.


A device used to lower the light output of a source, usually by reducing the wattage at which it is operated.   Dimmers come in various
forms such as rotary, slide, toggle and touch.


A directional luminaire that directs light downward.

efficacy (of a light source)

A commonly used measure of how effective a light source is in converting electrical
energy to lumens of visible light.  Efficacy is measure in lumens per watt (lm/W).

efficiency (of a luminaire)

The ratio of luminous flux (lumens) emitted by a luminaire to that emitted by the lamp or lamps used therein. Sometimes referred to as light output ration (LOR)

flange downlight

A recessed downlight luminaire with an outer trim mounted on the surface of the fixture.


In most fluorescent lamps, a mixture of argon and mercury gas contained in a glass bulb is stimulated by an electric current, producing ultraviolet rays. These rays strike a fluorescent phosphor coating on the interior surface of the bulb, causing it to emit visible light. Fluorescent lamps are more efficient than incandescent lamps because very little energy is lost as heat.

footcandle (fc)

A unit of measure of the intensity of light falling on a surface equal to one lumen (lm) per square foot.


A type of incandescent lamp which uses a halogen gas in order to increase both light output and rated life. Halogen lamps are known for moderately high efficiency, quality of light, and high rated life compared to regular incandescent lamps.

high intensity discharge (HID)

A family of gas-discharge arc lamps that create light by sending an electrical discharge between two electrodes and through a plasma, or ionized gas. An additional gas is generally used, and this gas serves as an easy way to classify the major types of high intensity lamps: mercury, sodium, and metal-halide.


An electric lamp consisting of a transparent or translucent glass housing containing a wire filament that emits light when heated by electricity.

initial light output

Also known as initial lumens, it is a lamp’s light output in lumens after the first 100 hours of operating.  It is a way to measure the output generated by a lighting system.

integrated lighting controls

A type of lighting control that allows for different preset lighting scenes; the light is controlled by a switch or with a remote
control and also through applications on a mobile device.

kilowatt hour (kWh)

The unit of measuring the power consumed by an electrical device over a period of time; 1 kilowatt-hour is equal to 1000 watts
used for 1 hour.

L70 rating

L70 is a way to measure LED lifetime by calculating the average rating in hours for a lamp to emit 70% of its initial lumen output.


A manufactured light source. For electric lamps, it includes the bulb, the base, and the internal structure that produces light.

lamp life

The value expressed in hours and represents the number of hours before the lamp (light bulb) is at half its original brightness.

(LED) light emitting diode

An electrical current passes through a microchip, which illuminates the tiny light sources, LEDs, and the result is visible light.  The heat LEDs produce is absorbed into a heat sink.  Because of their efficiency, LEDs make a good alternative to most conventional light sources.

LED driver

LED drivers regulate power and provide the LED lighting system with the right amount of electricity to perform optimally.


A glass or plastic element used in luminaires to refract, that is, to control, the distribution of light.

lumen (lm)

A measure of the quantity of light or luminous flux produced by a light source (lamp) that is visible to the human eye.  A standard 100-watt incandescent lamp has 1,700 lumens (lm).


A complete lighting unit consisting of a lamp or lamps, together with the parts designed to distribute light.  Also referred to as a light fixture, fitting or unit.


Also called brightness, it is a measure of how bright a surface will appear to an observer who is focused in the direction of the illuminated surface. The SI (International System of Units) unit for luminance is candelas (cd) per square foot.

multi-faceted reflector lamp (MR-lamp)

A low voltage halogen reflector lamp that is used in lighting applications where precise beam control is required, such as accent lighting.


The receptacle connected to the electrical supply.   Sockets allow lamps (light bulbs) to be safely and conveniently replaced.

solid state lighting (SSL)

A type of lighting that uses semiconductor LEDs as a source of illumination rather than electrical filaments, plasma or gas.


A device that turns a lamp or lamps on or off by completing or interrupting the power supplied to the lamp(s).

task lighting

Provides increased light for specific tasks in a room or work area that may already have some ambient light.


A device used to convert electrical energy from a higher to a lower voltage or vice versa.  When used with incandescent or halogen lamps, they typically step 120V distribution downward to 12V.

trimless downlight

A recessed downlight luminaire that seamlessly blends with the mounting surface for a clean, minimalist look.  Also referred to as a flangeless downlight.

voltage (V)

A measurement of the electromotive force (EMF) in an electrical circuit or device expressed in volts.  USA line voltage is 120V.

wattage (W)

The amount of electricity or power consumed by a light source expressed in watts.



LightWave Flexible LED Sheet Series

  • Cuttable & bendable
  • Consistent illumination
  • Customizable LED color options
  • Ideal for architectural, retail, and commercial applications
Learn More ▸

How can we help?

Contact Us ▸

DPC - Designer Power Communication

  • Powered USB & circuit breaker
  • Variety of outlet/USB combinations
  • Optional finishes available: Ivory, Light Almond, Nickel, White
  • Hospital-grade outlets and power cord option available
Learn More ▸

Sign Up to Receive Bright Ideas

Enter your email address below to receive periodic news and updates from Specialty Lighting.