quotient of the regularly transmitted part of the (whole) transmitted flux and the incident flux
Note 1 to entry:
Note 2 to entry: The regular transmittance has unit one.
Note 3 to entry: This entry was numbered 845-04-61 in IEC 60050-845:1987.
Note 4 to entry: This entry was numbered 17-1079 in CIE S 017:2011.