X-ray \x"ray\, ('eks-"rA) n. [1896]

1. (Med.) An image of the the internal body generated using an emulsion sensitive to x-rays
2. Any of the electromagnetic radiations of the same nature as visible radiation but having an extremely short wavelength of less than 100 angstroms that is produced by bombarding a metallic target with fast electrons in vacuum or by transition of atoms to lower energy states an d that has the properties of ionizing a gas upon passage through it, of penetrating various thicknesses of all solids, of producing secondar y radiations by impinging on material bodies, of acting on photographic films and plates as light does, and of causing fluorescent screens t o emit light.