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See also: Xray and x-ray





  1. The letter X in the ICAO spelling alphabet.


An early radiograph of Albert von Kölliker's left hand taken at a public lecture on 23 January 1896 by Wilhelm Röntgen, the discoverer of X-rays.
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Alternative forms[edit]


From X +‎ ray, a calque of German X-Strahl, coined by Wilhelm Conrad Röntgen upon his discovery of the rays in 1895, x signifying their unknown nature.


  • (UK) IPA(key): /ˈɛks ɹeɪ/
  • (US) IPA(key): /ˈɛks ˌɹeɪ/
  • (file)


X-ray (plural X-rays)

  1. Short wavelength electromagnetic radiation usually produced by bombarding a metal target in a vacuum. Used to create images of the internal structure of objects; this is possible because X-rays pass through most objects and can expose photographic film.
    X-rays are light with a wavelength between 0.1 and 10 nm.
  2. A radiograph: a photograph made with X-rays.
    "The doctor ordered some X-rays of my injured wrist."
    • 2012 June 2, Phil McNulty, “England 1-0 Belgium”, in BBC Sport[1]:
      And this friendly was not without its injury worries, with defender Gary Cahill substituted early on after a nasty, needless push by Dries Mertens that caused him to collide with goalkeeper Joe Hart, an incident that left the Chelsea defender requiring a precautionary X-ray at Wembley.
  3. An X-ray machine.
  4. The letter X in the ICAO spelling alphabet.


Derived terms[edit]

Related terms[edit]



X-ray (third-person singular simple present X-rays, present participle X-raying, simple past and past participle X-rayed)

  1. (transitive, informal) To take a radiograph of; to obtain an image of using X-ray radiation, especially for the purpose of medical diagnostic evaluation.
    Of course there was nothing wrong with my left wrist. They X-rayed the wrong arm!



X-ray (not comparable)

  1. Of or having to do with X-rays.
    I had to put my bags through an X-ray scanner at the airport.


Further reading[edit]