(1) Waves made up of oscillating electrical and magnetic fields perpendicular to one another and traveling at the speed of light. Can also be viewed as Photons or quanta of energy. Electromagnetic Radiation includes radio waves, microwaves, infrared, visible light, Ultraviolet radiation, X rays, and gamma rays. (2) Energy emitted as a result of changes in atomic and molecular energy states and propagated through space at the speed of light, i.e., energy transfer in the form of electromagnetic waves or particles that propagate through space at the speed of light. The term radiation is used commonly for this type of energy, although it actually has a broader meaning. Also called electromagnetic energy. See electromagnetic spectrum.