- the quality or condition of being bright
- the luminous aspect of a color (as distinct from its hue) by which it is regarded as approaching the maximum luminance of pure white or the lack of luminance of pure black
- The state or quality of being bright.
- The effect or sensation by means of which an observer is able to distinguish differences in luminance.
- The dimension of a color that represents its similarity to one of a series of achromatic colors ranging from very dim (dark) to very bright (dazzling).