candela

A basic unit of “luminous intensity” is light emitted by 1 candle

Symbol: cd / Base data: luminosity. SI base unit
Luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 1012 hertz and that has a radiant intensity in that direction of 1/683 W/sr.

Latin expression that is the source of the word “candle”

The intensity of light in a certain direction from the light source is called “luminous intensity”, and its SI base unit is the “candela”. Candela is a Latin word meaning “candle made with oil of an animal” and is the source of the word, “candle”. The definition of 1 candela is baffling, but it basically means the brightness emitted by a single candle.