<p><strong>Noun</strong></p><ul><li>The state or quality of being luminous.</li><li>Also called luminosity.</li><li>The quality or condition of radiating or reflecting light: the blinding luminance of the sun.</li><li>Optics: the 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.</li></ul>