Definition of X-ray in English:

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Pronunciation: /ˈeksˌrā/
(also x-ray or X ray)


1An electromagnetic wave of high energy and very short wavelength, which is able to pass through many materials opaque to light.
  • X-rays were formerly defined in terms of their wavelength, radiation of shorter wavelength than theirs being classed as gamma rays. They are now usually defined in terms of the mode of production: X-rays are produced by the deceleration of charged particles, especially electrons, or by electron transitions in atoms, while gamma rays arise from the radioactive decay of atomic nuclei.
Example sentences
  • Gamma rays are not particles but a form of electromagnetic radiation, like light, radio waves, and X-rays.
  • It was designed to study X-rays and gamma rays from solar flares.
  • Most known radiation dangers occur at the high end of the electromagnetic spectrum, and include X-rays and gamma rays.
1.1 [as modifier] informal Denoting an apparent or supposed faculty for seeing beyond an outward form: you didn’t need X-ray eyes to know what was going on
More example sentences
  • Television doctor Chris Steele has been given the all-clear from cancer after a ‘diagnosis’ from a Russian teenager who claims to have X-ray eyes.
  • I've also got X-ray vision, Super breath, and can leap four Range Rovers in a single bound.
  • Superman has X-ray vision: walls become permeable, transparent.
2A photographic or digital image of the internal composition of something, especially a part of the body, produced by X-rays being passed through it and being absorbed to different degrees by different materials.
Example sentences
  • Often used to identify fractures or tumors that may not be visible on an X-ray.
  • Having the ability to analyze X-rays and scans digitally from a remote location can be extremely valuable.
  • In this procedure, a special contrast material is injected into one of your milk ducts before the X-ray images are taken.
radiograph, radiogram, X-ray image/picture/photograph, roentgenogram
2.1An act of photographing someone with an X-ray: he will have an X-ray today would you send her for X-ray?
More example sentences
  • The doctor may need to take several tests, including blood tests or X-rays, to diagnose your child.
  • You may need X-rays or an ultrasound to check the kidneys and ureters.
  • Chief Executive Steve Ferres said that Ramsden was having an X-ray on the injury today to assess the extent of the damage.
3A code word representing the letter X, used in radio communication.


[with object]
Photograph or examine with X-rays: luggage bound for the hold is X-rayed
More example sentences
  • The body is X-rayed from many angles, and the X-rays are then analyzed by a computer.
  • Casualties are X-rayed to pinpoint the location of coins and some require surgery.
  • I was X-rayed, and had lots of nurses and doctors coming in and out of the room.


Translation of German X-Strahlen (plural), from X- (because, when discovered in 1895, the nature of the rays was unknown) + Strahl 'ray'.

For editors and proofreaders

Syllabification: X-ray

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