■ noun
1》 an electromagnetic wave of very short wavelength (between ultraviolet and gamma rays), able to pass through many materials opaque to light.
↘[as modifier ] informal denoting an apparent or supposed faculty for seeing beyond an outward form: ~ eyes.
2》 a photograph or other image of the internal structure of an object, especially a part of the body, produced by passing ~s through the object.
3》 a code word representing the letter X, used in radio communication.
■ verb photograph or examine with ~s.
Origin
translation of Ger. X-Strahlen (plural), from X- (because, when discovered in 1895, the nature of the rays was unknown) + Strahl 'ray'.