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radioactivity Line breaks: radio|activ¦ity
Pronunciation: /ˌreɪdɪəʊakˈtɪvɪti/

Definition of radioactivity in English:


[mass noun]
1The emission of ionizing radiation or particles caused by the spontaneous disintegration of atomic nuclei.
Example sentences
  • Early studies of radioactivity revealed that certain atomic nuclei were naturally radioactive.
  • They may also interact with nonmedical regulations, such as limits on electromagnetic emissions or radioactivity.
  • What makes dirty bombs particularly troublesome is that radioactivity, like fire, is something we deal with on a daily basis.
1.1Radioactive substances, or the radiation emitted by these: an escape of radioactivity
More example sentences
  • Small amounts of radioactivity escaped into the atmosphere.
  • The lack of safeguards is leaving thousands of children across central Scotland at risk of thyroid cancer following an escape of radioactivity.
  • They are comparing sediment taken from the Humber estuary - unpolluted by radioactivity - with other samples which contain the substance.

Definition of radioactivity in:

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Word of the day innocuous
Pronunciation: ɪˈnɒkjʊəs
not harmful or offensive