Radiation, emission and propagation of energy through space or through a material medium in the form of waves. The term may be extended to include streams of subatomic particles—alpha-rays or beta-rays—and cosmic rays. In the case of electromagnetic radiation (light), energy is transmitted in bundles (photons). Acoustic radiation is made up of sound waves.
See also: Radioactivity.
21st Century Webster's Family Encyclopedia21st Century Webster's Family Encyclopedia - Providence to Rafflesia