Radioactivity
Part of speech: noun
Definition: Spontaneous emission of ionizing radiation as a consequence of a nuclear reaction, or directly from the breakdown of an unstable nucleus. The radiation so emitted; including gamma rays, alpha particles, neutrons, electrons, positrons, etc.
Radiation
Part of speech: noun
Definition: The shooting forth of anything from a point or surface, like the diverging rays of light; as, the radiation of heat.The process of radiating waves or particles.The transfer of energy via radiation (as opposed to convection or conduction)Radioactive energy
Example sentence: When X-rays traverse matter of any kind, this matter becomes a source of a radiation similar in character to that of the primary radiation falling upon it.