Cars & Driving
- noun the luminous intensity of a surface in a given direction per unit of projected area of the surface, in candela per square metre; not the same as the apparent brightness
- The total light emitted or reflected from a surface in a given direction, per unit of projected area. The measurement must be made from the same direction the light is emitted from. May be expressed in foot-lamberts. The nearly obsolete term brightness (3) is also used for this concept.