optical radiation capable of causing a visual sensation directly
Note 1 to entry: There are no precise limits for the spectral range of visible radiation since they depend upon the amount of radiant flux reaching the retina and the responsivity of the observer. The lower limit is generally taken between 360 nm and 400 nm and the upper limit between 760 nm and 830 nm.
Note 2 to entry: This entry was numbered 845-01-03 in IEC 60050-845:1987.
Note 3 to entry: This entry was numbered 17-1402 in CIE S 017:2011.