can·de·la / kanˈdēlə; -ˈdelə/ (abbr.: cd) • n. Physics the SI unit of luminous intensity. One candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 10¹²Hz and has a radiant intensity in that direction of ¹/₆₈₃ watt per steradian.

candela (symbol cd) SI unit of luminous intensity. It is defined as 1/60 of the luminous intensity of a black body (which looks black) at atmospheric pressure and the temperature of solidification of platinum, 1772°C (3222°F).