Total energy radiated from an object per solid angle of measurement. Standard measurement unit W sr-1.
The radiant flux per unit solid angle, as from a point source; units are watts per steradian (W sr−1). See intensity.
In radiometry, radiant intensity is a measure of the intensity of electromagnetic radiation. It is defined as power per unit solid angle. The SI unit of radiant intensity is watts per steradian (W·sr-1).