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cumulative downward flux proportion, <of a light source, for a solid angle>
quotient of the cumulative flux for the solid angle under consideration and the downward flux of the light source
Note 1 to entry: The cumulative downward flux proportion has unit one.
Note 2 to entry: This entry was numbered 845-09-36 in IEC 60050-845:1987.
Note 3 to entry: This entry was numbered 17-266 in CIE S 017:2011.