/kan dee"leuh/ , n. Optics.
a unit of luminous intensity, defined as the luminous intensity of a source that emits monochromatic radiation of frequency 540 × 10 12 hertz and that has a radiant intensity of 1/683 watt/steradian: adopted in 1979 as the international standard of luminous intensity. Abbr.: Cd
[ 1945-50; ]