lu·mi·nos·i·ty 
(l′mə-nŏsĭ-tē)
(l′mə-nŏsĭ-tē)n. pl. lu·mi·nos·i·ties
1. The condition or quality of being luminous.
2. Something luminous.
3. The ratio of luminous flux at a specific wavelength to the radiant flux at the same wavelength. Also called luminosity factor.