Definitions

ACR   Apparent Color Temperature more of a guide to color that a description

CCT   Color correlated temperature Apparent color temperature is far more accurate that this description

DE-Double ended bulb End of life, the stage in the life of a metal halide lamp when the lamp begins to cycle

HID   Hatch metal halide 

HPS  high pressure sodium

HQI ballast for use with SE or DE lamps

Intensity see Lux  below K  

Kelvin a measurement of temperature, in lighting temperature and color are used interchangeably..

Lux (symbol: lx) is the SI unit of luminance. It is used as a measure of the intensity of light, with wavelengths weighted according to the luminosity function, a standardized model of human   brightness perception. In English, "lux" is used in both singular and plural

MH- metal halide

Phot  the unit of illuminance is the  phot. One  phot is equal to 10,000 lux.

SE- Single ended or Mogul base bulb

SI photometry units

 Luminous energy       Qv     lumen second                         units are at times referred to as talbots

Luminous flux              F       lumen                                    also called luminous power

Luminous intensity       Iv       candela                                  an SI base unit Luminance                  

Lv      candela per square meter        units are referred to as nits Illuminance                   

Ev      lux                                        measure of light incident on a surface Luminous emittance      

Mv     lux                                         measurement of light emitted from surfaces

Luminous efficacy   lumen per watt     ratio of luminous flux to radiant flux