radioactivity.

The spontaneous emission of particles or energy as unstable atomic nuclei change.

Use it for

Words that belong together

• radioactivity of a sample
• natural radioactivity

On the page

The radioactivity of the sample was measured rather than inferred from its appearance.

Natural radioactivity explained part of the recorded background signal.

Usage notes

Primary category: horror / sci-fi / gothic. Forms: Usually uncountable. Legacy lexical fields mirror sense 1 only. Use numbered sense fields for all meanings. Established modern English lexical item. No separate regional spelling or grammatical inflection entry. Writing functions: hazard description, speculative setting, bodily condition, scene explanation. Disciplines: genre writing, science-informed description, clinical and safety vocabulary. Commonness: moderately common.