ANSI - the American National Standards Institute, Inc is the coordinator of including lighting standards on a national level.

Arc Lamp - a discharge lamp in which the light is emitted by an arc tube.

Arc Tube - a tube made of clear quartz or ceramic material within a glass envelope of an HID lamp that contains the arc stream.

Ballast - a device used to create a starting voltage and stabilize electrical current for fluorescent lamps and HID lamps.

Base - the part of the lamp that connects to the socket.

Beam Candlepower - measure of beam intensity reflected from a reflector lamp.

Beam Spread - the angle of light distributed from a reflector lamp.

Color Rendering Index (CRI) - a rating for fluorescent lamp to examine its variance from outdoor natural light which has a defined CRI of 100. The rated ability of an artificial light source to render an objects true color.

Foot Candle - a unit of illumination. Equivalent of one candle emitting light on one square foot of surface area from one foot away.

Halogen - a tungsten incandescent filament lamp with a quartz envelope containing a proportion of halogen inert gas.

Kelvin Temperature Scale - a measurement of color appearance in degrees Kelvin (K).

Krypton -a heavier inert gas used in a variety of lamps to produce a brighter white light as well as longer lifetime by reducing the rate of filament decay.

Lumen - a measure of luminous flux. The quantity of light emitted by an artificial light source.

MOL - Maximum Overall Length. Length from the tip of the glass envelope to end of the base.

Nominal Length - overall length of a fluorescent lamp including sockets.  Generally, this measurement is from the back of one socket to the back of the opposing socket.

Watt - a unit of power consumption.