Radiation

• High energy particles or rays emitted during the nuclear decay processes.
• (ionizing radiation) Alpha particles, beta particles, gamma rays, x-rays, neutrons, high-speed electrons, high-speed protons, and other particles capable of producing ions. Radiation does not include non-ionizing radiation, such as radio- or microwaves, or visible, infrared, or ultraviolet light. Source: U.S. Nuclear Regulatory Commission
• Transmission of energy though space or any medium. Also known as radiant energy.
  Source: Terms of the Environment
• Energy released in the form of particles or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, and medical x-rays.