Meanings
nounradioactivity (usually uncountable, plural radioactivities)
plural radioactivities · alternative radio-activity
- uncountableusuallySpontaneous emission of ionizing radiation as a consequence of a nuclear reaction, or directly from the breakdown of an unstable nucleus.
Today, no one would intentionally smear radioactive materials on their face, but in 1933, the dangers of radioactivity were not yet fully understood.
2020 March 8, Jacopo Prisco, “When beauty products were radioactive”, in CNN - uncountableusuallyThe radiation so emitted; including gamma rays, alpha particles, neutrons, electrons, positrons, etc.
Synonyms & antonyms
nounthe spontaneous emission of a stream of particles or electromagnetic rays in nuclear decay
Similar
Broader
Also see
Synonym sets from Open English WordNet, CC BY 4.0.
Origin
From radioactive + -ity or radio- + activity.
Full word history & related roots →Translations
Afrikaans radioaktiwiteit, radioaktiwiteit
- radioaktiwiteitemission of ionizing radiation
- radioaktiwiteitradiation emitted
Basque erradioaktibitate, erradioaktibitate
- erradioaktibitateemission of ionizing radiation
- erradioaktibitateradiation emitted
Bulgarian радиоактивност, радиоакти́вност
- радиоактивност (radioaktivnost)emission of ionizing radiation
- радиоакти́вност (radioaktívnost)radiation emitted
Catalan radioactivitat, radioactivitat
- radioactivitatemission of ionizing radiation
- radioactivitatradiation emitted
Chinese Mandarin 放射性, 放射
- 放射性 (fàngshèxìng)emission of ionizing radiation
- 放射 (fàngshè)radiation emitted
- 放射線 /放射线 (fàngshèxiàn)radiation emitted
Czech radioaktivita, radioaktivita
- radioaktivitaemission of ionizing radiation
- radioaktivitaradiation emitted
Danish radioaktivitet
- radioaktivitetemission of ionizing radiation
Dutch radioactiviteit, radioactiviteit
- radioactiviteitemission of ionizing radiation
- radioactiviteitradiation emitted
Esperanto radioaktiveco
- radioaktivecoemission of ionizing radiation
Finnish radioaktiivisuus, radioaktiivisuus
- radioaktiivisuusemission of ionizing radiation
- radioaktiivisuusradiation emitted
French radioactivité, radioactivité
- radioactivitéemission of ionizing radiation
- radioactivitéradiation emitted
German Radioaktivität, Radioaktivität
- Radioaktivitätemission of ionizing radiation
- Radioaktivitätradiation emitted
Greek ραδιενέργεια, ραδιενέργεια
- ραδιενέργεια (radienérgeia)emission of ionizing radiation
- ραδιενέργεια (radienérgeia)radiation emitted
Hebrew רדיואקטיביות, קרינה
- רדיואקטיביות (radioaktíviyut)emission of ionizing radiation
- קרינה (kriná)radiation emitted
Hindi विकिरणशीलता, विकिरण
- विकिरणशीलता (vikirṇaśīltā)emission of ionizing radiation
- विकिरण (vikiraṇ)radiation emitted
Icelandic geislavirkni
- geislavirkniemission of ionizing radiation
Irish radaighníomhaíocht, radaighníomhaíocht
- radaighníomhaíochtemission of ionizing radiation
- radaighníomhaíochtradiation emitted
Japanese 放射能
- 放射能 (hōshanō)emission of ionizing radiation
Korean 방사능
- 방사능 (bangsaneung)emission of ionizing radiation
Lithuanian radioaktyvumas
- radioaktyvumasemission of ionizing radiation
Norwegian Bokmål radioaktivitet, radioaktivitet
- radioaktivitetemission of ionizing radiation
- radioaktivitetradiation emitted
Polish radioaktywność, promieniotwórczość
- radioaktywnośćemission of ionizing radiation
- promieniotwórczośćemission of ionizing radiation
Portuguese radioatividade, radioatividade
- radioatividadeemission of ionizing radiation
- radioatividaderadiation emitted
Romanian radioactivitate
- radioactivitateemission of ionizing radiation
Russian радиоакти́вность, радиоакти́вность
- радиоакти́вность (radioaktívnostʹ)emission of ionizing radiation
- радиоакти́вность (radioaktívnostʹ)radiation emitted
Scottish Gaelic rèididheachd, rèididheachd
- rèididheachdemission of ionizing radiation
- rèididheachdradiation emitted
Slovak rádioaktivita
- rádioaktivitaradiation emitted
Spanish radioactividad, radioactividad
- radioactividademission of ionizing radiation
- radioactividadradiation emitted
Swedish radioaktivitet, radioaktivitet
- radioaktivitetemission of ionizing radiation
- radioaktivitetradiation emitted
Tagalog karagilapan
- karagilapanemission of ionizing radiation
Tamil கதிரியக்கம், கதிரியக்கம்
- கதிரியக்கம் (katiriyakkam)emission of ionizing radiation
- கதிரியக்கம் (katiriyakkam)radiation emitted
Thai กัมมันตภาพรังสี, รังสี
- กัมมันตภาพรังสีemission of ionizing radiation
- รังสี (rang-sǐi)radiation emitted
Turkish radyoaktivite, radyoaktivite
- radyoaktiviteemission of ionizing radiation
- radyoaktiviteradiation emitted
Ukrainian радіоактивність, радіоакти́вність
- радіоактивність (radioaktyvnistʹ)emission of ionizing radiation
- радіоакти́вність (radioaktývnistʹ)radiation emitted
Vietnamese sự phóng xạ
- sự phóng xạemission of ionizing radiation
Welsh ymbelydredd, ymbelydredd
- ymbelydreddemission of ionizing radiation
- ymbelydreddradiation emitted
Cite this entry
APA
radioactivity. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/radioactivity
MLA
“radioactivity.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/radioactivity. Accessed November 2, 2026.
Chicago
WatkinsX Dictionary, s.v. “radioactivity,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/radioactivity.
Source: radioactivity on Wiktionary, CC BY-SA 4.0.