X-ray. Electromagnetic radiation, Wilhelm Röntgen, Radiography, X-ray crystallography, X-ray tube, X-ray fluorescence, Bremsstrahlung, X-ray image intensifier, Chest radiograph, Energy-dispersive X-ray spectroscopy, Abdominal x-ray, X-ray astronomy, X-ray microscope, X-ray generator, X-ray optics, Backscatter X-ray, Small-angle X-ray scattering, X-ray vision, X-ray absorption spectroscopy, X-ray nanoprobe