radiance

A measure of the intensity of the radiant energy flux emitted by a body in a given direction.

A measure of the intrinsic radiant energy flux intensity emitted by a radiator in a given direction, expressed in units of energy per unit time per unit solid angle.

Radiant power, in a given direction, per unit solid angle per unit of projected area of the source, as viewed from the given direction. Note: Radiance is usually expressed in watts per steradian per square meter.