illuminance averaged over a specified surface
Note 1 to entry: When stating the average illuminance it is necessary to provide a clear indication of the type of illuminance at the points of the surface, i.e. horizontal, vertical, spherical, cylindrical or semi-cylindrical.
Note 2 to entry: The average illuminance is expressed in lux (lx = lm·m−2).
Note 3 to entry: This entry was numbered 17-63 in CIE S 017:2011.