WordReference Random House Unabridged Dictionary of American English © 2024lu•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 - 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 direction
Symbol: L
Etymology: 19th Century: from Latin lūmen light