The brightness of an object, expressed as the luminous flux per unit solid angle per unit projected area, measured in lamberts or in candelas per square meter. [L. lumino, to light up, fr. lumen, light]
* * *
1) the quality or state of being luminous
2) the luminous intensity of a surface in a given direction per unit of projected area
* * *
lu·mi·nance (L) (looґmĭ-nəns) the luminous intensity per unit of projected area of a surface as viewed in a given direction.Medical dictionary. 2011.