Natural Phenomenon or Process
radioactivity Audio
ra·di·o·ac·tiv·i·ty [ rey-dee-oh-ak-tiv-i-tee ]
Definitions related to radioactivity:
  • The quality of emitting or the emission of corpuscular or electromagnetic radiations consequent to nuclear disintegration, a natural property of all chemical elements of atomic number above 83 and possible of induction in all other known elements.
    NCI
    U.S. National Cancer Institute, 2021
  • The spontaneous transformation of a nuclide into one or more different nuclides, accompanied by either the emission of particles from the nucleus, nuclear capture or ejection of orbital electrons, or fission. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
    NLM Medical Subject Headings
    U.S. National Library of Medicine, 2025
Try this search on: Farlex, Merriam-Webster, Oxford Dictionary, or Wordnik

This content should not be used in place of medically-reviewed decision support reference material or professional medical advice. Some terms may have alternate or updated definitions not reflected in this set. The definitions on this page should not be considered complete or up to date.