Grey body radiation is also referred to as diffuse radiation, blackbody radiation, and thermal radiation. Diffuse radiation refers to the radiation emitted by any object that is at a temperature higher than absolute zero. Blackbody radiation, on the other hand, is the radiation emitted by an object that absorbs all incident radiation. Thermal radiation, commonly used in the field of thermodynamics, describes the emission of light from all objects at temperatures above absolute zero. These three synonyms all describe the same phenomenon in slightly different ways, and are used interchangeably in scientific literature.