Radiation that is of equal intensity in all directions.
Diffuse solar radiation which has the same intensity in all directions.
Equal radiation in all direction (e.g. the electric field from a point charge, or light radiating from a star)
Radiation with constant radiance in all directions.
Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented. It radiates uniformly in all directions from a point source sometimes called an isotropic radiator. The radiation may be electromagnetic, audio or composed of other elementary particles.