radioactivity
noun
ra·dio·ac·tiv·i·ty
| \ ˌrā-dē-ō-ak-ˈti-və-tē
\
\
Definition of radioactivity
: 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
An explosion at a Russian military base killed three personnel and caused a brief spike in radioactivity in a nearby Russian city. — Kyle Mizokami, Popular Mechanics, "Missile Explosion Prompts Radiation Warnings in Russia," 8 Aug. 2019 The imminent blockbuster and Finals MVP’s free agency looms over the entire NBA, yet here were Ball and James, in the flesh, laughing and dapping and … oh wait, there’s another spike in radioactivity on the other end of the floor. — Jake Fischer, SI.com, "Zion Williamson Creates Raucous Atmosphere in Summer League Debut," 5 July 2019 Unprotected persons caught in the blast—or venturing into the blast zone afterward—could be exposed to dangerous levels of radioactivity, leading to radiation sickness or cancer. — Kyle Mizokami, Popular Mechanics, "The Pentagon Wants VR To Train for Nuclear War," 9 July 2019 The first piece of land transferred to the city, a 75-acre hilltop region known as Parcel A, was not tested for radioactivity. — Jason Fagone, SFChronicle.com, "Report: Navy altered Hunters Point cleanup to cover, not remove, toxic soil," 14 Aug. 2019 The scientific mission's samples show levels of radioactivity at the site up to 800,000 higher than normal, the Norwegian Radiation and Nuclear Safety Authority said in a statement. — NBC News, "Soviet nuclear sub that sank off Norway in 1989 still emitting radiation," 10 July 2019 Experts carefully analyzed the transfer of radioactivity to crops grown in the exclusion zone around the site of the world’s worst nuclear disaster. — Fox News, "Chernobyl vodka: Scientists create booze from disaster's exclusion zone," 13 Dec. 2010 That impending trade is, of course, the backdrop for Friday’s radioactivity. — Jake Fischer, SI.com, "Zion Williamson Creates Raucous Atmosphere in Summer League Debut," 5 July 2019 Starting in the 1990s, physicists developed high-precision experiments to study how neutrons — particles found in the nuclei of atoms — break down into protons, a process related to radioactivity. — NBC News, "Scientists are searching for a mirror universe. It could be sitting right in front of you.," 30 June 2019These example sentences are selected automatically from various online news sources to reflect current usage of the word 'radioactivity.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.
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More Definitions for radioactivity
radioactivity
noun
ra·dio·ac·tiv·i·ty
| \ ˌrā-dē-ō-ak-ˈti-və-tē
\
\
Kids Definition of radioactivity
1
: the giving off of rays of energy or particles by the breaking apart of atoms of certain elements (as uranium)
2
: the rays or particles that are given off when atoms break apart
radioactivity
noun
ra·dio·ac·tiv·i·ty
| \ -ak-ˈtiv-ət-ē
\
\
plural radioactivities
Medical Definition of radioactivity
: 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
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