noun
radioactivity
ray-deer-uuak-TIH-vih-tee
noun
1
The spontaneous release of radiation from unstable atomic nuclei as they break down.
"Scientists measured the radioactivity of the soil samples near the plant."
How to Use Radioactivity
Learner’s notesIn plain EnglishThe physical process (or the radiation itself) produced when unstable atomic nuclei decay.
Common pairings
levels of radioactivity
measure radioactivity
Word Forms
radioactivities plural
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Scientists measured the _____ of the soil samples near the plant.
Etymology
From "radioactive" plus the noun-forming suffix "-ity".