[9.4.8]

NOTE: This term’s definition was changed in RP-16-17 Addendum 1. Deletions have a strike-through. New text is bold.

The ratio of luminous flux (lumens) emitted by a luminaire to that emitted by the lamp or lamps used therein.

The luminous flux emitted by a luminaire, divided by the luminous flux emitted by the source(s). Sometimes called light output ratio (LOR).