| candela | <physics, unit> The SI unit of luminous intensity, 1 lumen per m2; the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 1012 hertz and that has a radiant intensity in that direction of 1/683 watt per steradian (solid angle). Synonym: candle. Abbreviation: cd Origin: L. (05 Mar 2000) |
|---|