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Definition of "radioactivity" []

  • Spontaneous emission of radiation, either directly from unstable atomic nuclei or as a consequence of a nuclear reaction. (noun)
  • The radiation, including alpha particles, nucleons, electrons, and gamma rays, emitted by a radioactive substance. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Use "radioactivity" in a sentence
  • "Since Marie Curie coined the word "radioactivity" in 1898, we've struggled with nuclear-weapons proliferation, we've debated the role of radiation in medical treatment, and we've considered nuclear energy as an alternative energy source to counter climate change."
  • "Especially appealing are the ones inspired by Madame Curie, two-time Nobel prize winner who discovered radium and polonium and coined the term "radioactivity.""
  • "She may have had to exist in a state of denial to accomplish what she did: she opened up the field of radiation, coining the word radioactivity; she not only found two new elements, she found a new way to find them, using the tools of physics."