Luminous Flux: Symbol Φ, Unit: lumen( Lm), Definition:: The rate of flow of light per unit of time, especially the flux of visible light expressed in lumens.
Luminous flux in lumens = Radiant power (watts) x 683 lumens/watt x luminous efficacy

Luminous intensity: Symbol I, Unit: Candela cd, Definition:: The luminous flux density per solid angle as measured in a given direction relative to the emitting source.

Illuminance: Symbol E, Unit: lux (Lm/m2), Definition: the unit of illuminance in the International System of Units (SI). It is defined in terms of lumens per meter squared (lm/m 2 ).
Lux=Lumen÷SquareMeter

Luminance: Symbol L, units: cd/m2, Definition:: Luminous intensity per unit projected area of any surface, as measured from a specific direction.

Luminous efficiency: Unit: Lm / w, Definition:: The ratio of the total emitted luminous flux, in lumens, to the total electric power consumption in watts.

Average life : Unit: hours, Definition:: The length of time during which >50% of the lamps reach the end of their individual lives.

Economic life: Unit: hours, Definition: the hours of operation a lamp is designed to provide in terms of optimum light output, aesthetic quality, and economic energy consumption. The "economic life" of lamps is generally defined as 60% of the lamp’s rated life. For example. outdoor lighting bulbs are designed as 70 percent to the rated life, and indoor lighting bulbs are 80%.

Color Temperature: Unit K(Kelvin), Definition: Of a solid surface, that temperature of a blackbody from which the radiant energy has essentially the same spectral distribution as that from the surface.
- Color Temperature >5000k: the light color belongs to cool and cold one(white with a little blue),cold atmosphere.
- Color Temperature 3300-5000k: the light color ranks middle(white), refreshing atmosphere.
- Color Temperature <3300k: the light color belongs to warm one(red with white),steady-going atmosphere.

Color rendering index(CRI): Unit: Ra, Definition:it is a measure of the ability of a light source to reproduce the colors of various objects being lit by the source.