Candela

Abbreviated cd, the International System of Units standard unit of measurement of luminous intensity. The candela is equal to the luminous intensity in a given direction of a source that emits monochromatic radiation of frequency 540 x 10¹² hertz and has a radiant intensity in that direction of 1/683 watt per unit solid angle

The measurement of luminous intensity is often expressed as the ratio of candelas per square meter (cd/m²), representing a luminous intensity of candelas radiating from a surface whose area is one square meter.

The luminous intensity of computer monitors, such as CRT monitors, is often expressed in candelas.