Added 9 October 2026
radioactivity
/ˌreɪdɪəʊakˈtɪvɪti/ noun
noun Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about radioactivity at Wordnik → Where our words come from →
- The spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay.
Origin
From radioactive + -ity or radio- + activity.
From Wiktionary, via Kaikki.org (CC BY-SA)