noun 1. (often plural) Physics electromagnetic radiation of shorter wavelength than light (5 × 10-9 to 6 × 10-12 m) which is able to penetrate solids, ionise gases, and expose photographic plates; roentgen ray.
2. an examination of the interior of the body of a person or animal or the interior of an opaque substance by means of an apparatus using X-rays.
–verb (t) 4. to examine by means of X-rays.
5. to make an X-ray radiograph of.
6. to treat with X-rays.[German: translation of X-strahlen, so called because their nature was not known; coined in 1895 by their discoverer WK Roentgen, 1845–1923]