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diffraction

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Etymology and origin of the French word diffraction

Confidence
Established
Formation
Borrowing
First attested
1666 Journal des savants More words from the 17th century
From
Latin diffractum
Ultimate origin
Latin frangō

Pronunciation

  • /di.fʁak.sjɔ̃/[1]

Forms

diffraction f (plural diffractions)[1]

Etymology

It is a learned derivative, from Latin diffractum (“broken in pieces”), the supine of diffringō (“to break in pieces, shatter”), with the suffix -tion.[2][3][4] Rey adds that it was modelled on réfraction.[4] The Latin verb is formed from dis-, expressing scattering, and frangō (“to break”), the verb behind fraction.[4][5]

Earliest recorded meaning

It is first recorded in 1666 in the Journal des savants, as a term of optics: the bending of light rays as they pass the edge of an opaque body.[2][4][3]

Semantic evolution

The word has stayed technical.[4] From light it was extended by analogy to other waves and radiation: in acoustics and radio for sound and radio waves that bend round obstacles, and for beams of particles such as neutrons and X-rays.[2][3][6] In the 20th century it was also used figuratively, as by Mounier in 1946.[2]

Physicists formed a family around it: diffringent (1738) from the Latin present participle, diffracter (1838) on the model of réfracter, diffractif (1846) and diffractomètre (about 1950).[4]

Timeline

  • 1666 – First recorded in the Journal des savants.[2][4]
  • 1738 – The related adjective diffringent appears.[4]
  • 1838 – The verb diffracter is formed from it.[4]
  • 1846 – The adjective diffractif is recorded.[4]
  • 1946 – Mounier uses it figuratively.[2]
  • c. 1950 – Diffractomètre names the instrument that measures diffraction.[4]

Meanings

Noun

  1. (physics, optics) The deviation of light rays passing close to the edges of an opaque body.[2][6][7]
  2. (physics) By extension, the same phenomenon in other waves and radiation, such as sound, radio waves, X-rays or particle beams: diffraction des rayons X.[2][6][8]
  3. (figurative) A scattering or breaking up, as of a force or idea.[2]

Word family

  • diffracter
  • diffractif
  • diffractomètre

References

  1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
  2. ^ a b c d e f g h i Trésor de la langue française informatisé (2004), ATILF – CNRS & Université de Lorraine, atilf.fr/tlfi; electronic version of Imbs, Paul; Quemada, Bernard, eds. (1971–1994), Trésor de la langue française, Paris: CNRS / Gallimard
  3. ^ a b c Guilbert, Louis; Lagane, René; Niobey, Georges, eds. (1971–1978; 1989), Grand Larousse de la langue française, Paris: Larousse
  4. ^ a b c d e f g h i j k Rey, Alain, ed. (1992), Dictionnaire historique de la langue française, Paris: Le Robert
  5. ^ Rey, Alain, ed. (2005), Le Grand Robert de la langue française, electronic version, Paris: Le Robert
  6. ^ a b c Rey-Debove, Josette; Rey, Alain, eds. (2007), Le Petit Robert de la langue française, Paris: Le Robert
  7. ^ Dictionnaire Le Robert en ligne, dictionnaire.lerobert.com (accessed 2024)
  8. ^ Dictionnaire de français Larousse, larousse.fr/dictionnaires/francais (accessed 2024)

Related etymologies

Cite this entry

“Diffraction.” Etymologically, 15 Nov. 2026, etymologically.com/fr/diffraction. Accessed 15 Nov. 2026.

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