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radioactivity

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Etymology and origin of the English word radioactivity

Confidence
Established
Formation
Compound
First attested
1899 the journal Science More words from the 19th century
Ultimate origin
French radioactivité
Etymology tree
inherited borrowed derived
English activity
English radioactivity
From the same root
English inactivity ← activity

Pronunciation

  • /ˌreɪdɪəʊakˈtɪvɪti/[1]

Etymology

It is formed from English radio- + activity,[2][3][4][5] after radioactive and French radioactivité,[2] which Etymonline and Klein give as its direct source.[6][7] The French word was coined in 1898 by Pierre and Marie Curie.[6][7][2] Their adjective radioactif, from the same year, joins radio-, the combining form of Latin radius (“ray”), to actif (“active”).[6][2] The astronomical sense has a formation of its own, with the combining form that refers to radio waves.[2]

Earliest recorded meaning

The property or condition of being radioactive: 1899, in the journal Science of 3 February,[2][3][6] a year after the French word.[2][6] Dictionary.com places the word more loosely in 1895–1900.[5]

Semantic evolution

From the start the word covered both the property and what it produces, the radiation emitted and radioactive material in a dispersed form.[2][6][4] In 1903 it was also used for the branch of science that studies these phenomena, a rare use that French has only much later, by 1964.[2] A figurative use for the passing on of intense energy appears in 1922, in C. E. Montague's Disenchantment, and French has the same use by 1923.[2] From 1959 the word also named the emission of radio waves by a celestial object.[2]

Timeline

  • 1899 – the property of being radioactive; the radiation emitted.[2][3][6]
  • 1903 – the branch of science dealing with these phenomena (rare).[2]
  • 1922 – figurative, the communication of intense energy.[2]
  • 1959 – the emission of radio waves by a celestial object.[2]

Meanings

Noun

  1. The spontaneous emission of radiation (alpha or beta rays and sometimes gamma rays) from disintegrating atomic nuclei, as in radium and uranium.[8][3]
  2. The radiation emitted, or radioactive material in dispersed form: Sensors detected radioactivity in the river mud.[3][2]
  3. (rare) The branch of science that studies these phenomena.[2][4]
  4. (figurative) A quality of passing on intense energy, or the energy itself.[2]
  5. The emission of radio waves by a celestial object.[2]

References

  1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i j k l m n o p q r s Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
  3. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
  4. ^ a b c Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
  5. ^ a b Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
  6. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
  7. ^ a b Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
  8. ^ Collins English Dictionary (2023), Glasgow: HarperCollins
Cite this entry

“Radioactivity.” Etymologically, 6 Nov. 2026, etymologically.com/en/radioactivity. Accessed 7 Nov. 2026.

Last edited on . ·