Definitions for x-radiationˈɛksˌreɪ diˈeɪ ʃən
Random House Webster's College Dictionary
x-ra•di•a•tionˈɛksˌreɪ diˈeɪ ʃən(n.)
radiation in the form of x-rays.
X ray, X-ray, X-radiation, roentgen ray(noun)
electromagnetic radiation of short wavelength produced when high-speed electrons strike a solid target
obtaining images by the use of X rays