X ray :  n 1: electromagnetic radiation of short wavelength produced when high-speed electrons strike a solid target [syn: X ray, X-radiation, roentgen ray] 2: a radiogram made by exposing photographic film to X rays; used in medical diagnosis [syn: roentgenogram, X ray, X-ray picture, X-ray photograph]

Becquerel ray, ECG, EEG, EKG, Grenz ray, Photostat, Roentgen ray, X radiation, X-ray movie, Xerox, actinic ray, actinism, alpha radiation, alpha ray, anode ray, atomic beam, atomic ray, beam, beam of light, beta radiation, beta ray, blood bank, calotype, canal ray, capture on film, cathode ray, charity ward, chest X-ray, clinic, consultation room, cosmic radiation, cosmic ray, cosmic ray bombardment, delivery room, dispensary, electrocardiogram, electrocorticogram, electroencephalogram, electroencephalograph, electromyogram, electron emission, emergency, encephalogram, encephalograph, examining room, fever ward, film, gamma radiation, gamma ray, gleam, hospital room, infrared ray, infraroentgen ray, intensive care, invisible radiation, irradiate, isolation, labor room, laboratory, leam, maternity ward, microfilm, mug, nuclear rays, nursery, operating room, orthodiagram, pan, patch, pencil, pharmacy, photofluorogram, photofluorograph, photogram, photograph, photomap, photon, positive ray, prison ward, private room, pyelogram, radiation, radiogram, radiograph, radiorays, radiumize, ray, ray of light, recovery room, ribbon, ribbon of light, roentgenize, roentgenogram, roentgenograph, scotograph, semi-private room, shadowgram, shadowgraph, shoot, skiagram, skiagraph, snap, snapshoot, snapshot, solar rays, streak, stream, stream of light, streamer, surgery, take a photograph, talbotype, therapy, treatment room, ultraviolet ray, violet ray, ward,

Xiphura \Xi*phu"ra\, n. pl. [NL., from Gr. xi`fos sword + ? tail.] (Zo["o]l.) Same as Limuloidea. Called also Xiphosura. X ray. See under Ray.

. So called from the discoverer, W. C. R["o]ntgen. X ray, the R["o]ntgen ray; -- so called by its discoverer because of its enigmatical character, x being an algebraic symbol for an unknown quantity.