symmetrical luminous intensity distribution, <of a light source>
distribution of luminous intensity having at least one axis of symmetry or at least one plane of symmetry
Note 1 to entry: Sometimes the term "symmetrical luminous intensity distribution" is used in the sense of the term "rotationally symmetrical luminous intensity distribution". This usage is to be discouraged.
Note 2 to entry: This entry was numbered 845-09-25 in IEC 60050-845:1987.
Note 3 to entry: This entry was numbered 17-1295 in CIE S 017:2011.