radioactivity
noun/ˌreɪdɪəʊakˈtɪvɪti/
Etymology From radioactive + -ity or radio- + activity.
1
Usually Spontaneous emission of ionizing radiation as a consequence of a nuclear reaction, or directly from the breakdown of an unstable nucleus.
- Today, no one would intentionally smear radioactive materials on their face, but in 1933, the dangers of radioactivity were not yet fully understood.2020 March 8, Jacopo Prisco, “When beauty products were radioactive”, in CNN:
2
Usually The radiation so emitted; including gamma rays, alpha particles, neutrons, electrons, positrons, etc.
- Derived terms
- nonradioactivity
- Related terms
- activity, nuclear radiation, radiation, radiation poisoning, radio-, radioactive decay, becquerel, curie, half-life