radioactivity
/ˌreɪdɪəʊakˈtɪvɪti/
radioactivity
English
Noun Top 23,221
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Definition
Spontaneous emission of ionizing radiation as a consequence of a nuclear reaction, or directly from the breakdown of an unstable nucleus.
Etymology
From radioactive + -ity or radio- + activity.
Example Sentences
- "Today, no one would intentionally smear radioactive materials on their face, but in 1933, the dangers of radioactivity were not yet fully understood."
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