radioactivity

noun

ra·​dio·​ac·​tiv·​i·​ty ˌrā-dē-ō-ak-ˈti-və-tē How to pronounce radioactivity (audio)
: the property possessed by some elements (such as uranium) or isotopes (such as carbon 14) of spontaneously emitting energetic particles (such as electrons or alpha particles) by the disintegration of their atomic nuclei
also : the rays emitted

Examples of radioactivity in a Sentence

Recent Examples on the Web Minimal radioactivity was released, and there were no immediate deaths. Trip Gabriel, New York Times, 6 Jan. 2024 After a meltdown at the Fukushima plant in 2011 following an earthquake and a tsunami, the EU restricted food imports from 10 prefectures in Japan and started requiring pre-export tests on food products for radioactivity. Olesya Dmitracova, CNN, 14 July 2023 What was the difference between fire and radioactivity, exactly? Martin Aitken, Harper's Magazine, 16 Aug. 2023 Especially challenging were very specific military requirements regarding the half-life of the radioisotopes that would be dispersed by the weapons and the intensity of radioactivity emitted. William C. Potter, Foreign Affairs, 15 Dec. 2023 For several years now, researchers have been able to conclusively link wild boars’ excessive radioactivity to their diet. Stephen C. George, Discover Magazine, 7 Nov. 2023 Many mines have high levels of radioactivity, and a high risk of collapse, leading to injury or death. Marx Itabelo Lwabanya, Scientific American, 1 Dec. 2023 While Novo Nordisk began clinical testing of liraglutide for obesity, Knudsen’s team embarked on a series of studies using radioactivity to trace the drug’s path through the bodies of mice. Megan Molteni and Elaine Chen, STAT, 30 Sep. 2023 Tides, radioactivity, chemistry and youth: These ingredients, when mixed in the right way, can produce — and sustain — oceans on these icy moons. Quanta Magazine, 2 Nov. 2023

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'radioactivity.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

International Scientific Vocabulary

First Known Use

1899, in the meaning defined above

Time Traveler
The first known use of radioactivity was in 1899

Dictionary Entries Near radioactivity

Cite this Entry

“Radioactivity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/radioactivity. Accessed 29 Mar. 2024.

Kids Definition

radioactivity

noun
ra·​dio·​ac·​tiv·​i·​ty -ˌak-ˈtiv-ət-ē How to pronounce radioactivity (audio)
: the giving off of rays of energy or particles by the breaking apart of atoms of certain elements (as uranium)

Medical Definition

radioactivity

noun
ra·​dio·​ac·​tiv·​i·​ty -ak-ˈtiv-ət-ē How to pronounce radioactivity (audio)
plural radioactivities
: the property possessed by some elements (as uranium) or isotopes (as carbon 14) of spontaneously emitting energetic particles (as electrons or alpha particles) by the disintegration of their atomic nuclei

More from Merriam-Webster on radioactivity

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!