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
Recent Examples of radioactivity from the Web
Many theories exist, ranging from alien life to radioactivity in the rock below, but none has withstood scientific testing.
That means any charge in the tools today would have been generated after they were buried, as the surrounding sediments bombarded the stone with natural radioactivity.
The painters at The Radium Dial Co. and The Radium Luminous Materials Corp. were told repeatedly that radium wasn’t dangerous, even though warnings about radioactivity had been trickling out since 1906.
Some radioactivity was released into the air and ocean, and the plant’s operator was faulted for inadequate safety measures.
It has not been occupied in 20 years and remains contaminated by radioactivity.
In Japan, the Korean crisis has led to soaring sales of bomb shelters and air purifiers to protect against radioactivity and toxic chemicals.
Almost every day our bodies come in contact with radiation, whether flying in an airplane, walking by geotechnical tests sites, or even sitting by people who currently receiving administered radioactivity for medical treatment.
Depending on the amount of radioactivity in the soil, the resulting images contain a few white dots or enough to create nebula-like white splotches.
These 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.
Origin and Etymology of radioactivity
International Scientific Vocabulary
First Known Use: 1899See Words from the same year
RADIOACTIVITY Defined for Kids
Definition of radioactivity for Students
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
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
Seen and Heard
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