- a state or quality of radiating or reflecting light
- a measure (in candelas per square metre) of the brightness of a point on a surface that is radiating or reflecting light. It is the luminous intensity in a given direction of a small element of surface area divided by the orthogonal projection of this area onto a plane at right angles to the directionSymbol: L
WordReference Random House Unabridged Dictionary of American English © 2026
lu•mi•nance
(lo̅o̅′mə nəns),USA pronunciation n.
- the state or quality of being luminous.
- Also called luminosity. the quality or condition of radiating or reflecting light:the blinding luminance of the sun.
- Opticsthe quantitative measure of brightness of a light source or an illuminated surface, equal to luminous flux per unit solid angle emitted per unit projected area of the source or surface.
- Latin lūmin- (stem of lūmen) light + -ance
- 1875–80
Collins Concise English Dictionary © HarperCollins Publishers::
luminance /ˈluːmɪnəns/ n
'luminance' also found in these entries (note: many are not synonyms or translations):
brilliance
- nit
- apostilb
- brightness
- foot-lambert
- lambert
- luminosity
- millilambert
- stilb