Xray

1 of 3

communications code word

ˈeks-ˌrā 

—used as a code word for the letter x

x-ray

2 of 3

verb

ˈeks-ˌrā 

variants often X-ray

x-rayed; x-raying; x-rays; often X-rayed; X-raying; X-rays

transitive verb

: to examine, treat, or photograph with X-rays

X-ray

3 of 3

noun

ˈeks-ˌrā 

1

: any of the electromagnetic radiations that have an extremely short wavelength of less than 100 angstroms and have the properties of penetrating various thicknesses of all solids, of producing secondary radiations by impinging on material bodies, and of acting on photographic films and plates as light does

2

: a photograph obtained by use of X-rays

X-ray adjective

Examples of Xray in a Sentence

Recent Examples on the Web

Noun

Using the X-ray spacecraft XRISM (X-ray Imaging and Spectroscopy Mission), astronomers have observed stellar winds from a hypergiant star feeding an extreme stellar remnant known as a neutron star, left over after a massive star dies. — Robert Lea, Space.com, 24 Sep. 2026

Salort-Pons’s X-ray analysis showed that this costume was the one Velázquez had originally depicted Olivares wearing. — Maximilíano Durón, ARTnews.com, 23 Sep. 2026

Brown sent the belongings through the X-ray machine again to narrow down its location. — Kelly McGreal, FOXNews.com, 23 Sep. 2026

Geiger-Müller and neutron detectors found no detectable gamma or X-ray emissions, while neutron counts remained statistically indistinguishable from background during about five days of monitoring. — Neetika Walter, Interesting Engineering, 22 Sep. 2026

Word History

First Known Use

Communications Code Word

1943, in the meaning defined above

Verb

1899, in the meaning defined above

Noun

1896, in the meaning defined at sense 1

Kids Definition

x-ray

1 of 2 verb

ˈeks-ˌrā

often capitalized X

: to examine, treat, or photograph with X-rays

X-ray

2 of 2 noun

ˈeks-ˌrā

1

: an electromagnetic radiation of an extremely short wavelength that is able to penetrate various thicknesses of solids and to act on photographic film as light does

2

: a photograph taken by the use of X-rays

X-ray adjective

Etymology

Noun

from German X-Strahl "X-ray," from the use of x to represent an unknown value

Word Origin

In 1895, a German scientist, Wilhelm Conrad Röntgen, was experimenting with an electric current passing through a vacuum in a glass tube. He found that a piece of material that glows only when electricity passes through it began to glow even though it was not inside the tube. Röntgen tried to shield the material from the tube. However, he found that the material glowed even when it was shielded by paper or wood. Only a shield of metal stopped the glowing. He guessed that an unknown invisible ray created inside the glass tube was causing this to happen. Since he knew nothing about this mysterious ray, Röntgen called it X-Strahl in German, which translates as X-ray in English. He was using the letter x, which had long been used in mathematics for an unknown value.

Medical Definition

x-ray

1 of 2 transitive verb

ˈeks-ˌrā 

often capitalized X

: to examine, treat, or photograph with X-rays

X-ray

2 of 2 noun

1

: any of the electromagnetic radiations of the same nature as visible radiation but of an extremely short wavelength 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 and that has the properties of ionizing a gas upon passage through it, of penetrating various thicknesses of all solids, of producing secondary radiations by impinging on material bodies, of acting on photographic films and plates as light does, and of causing fluorescent screens to emit light

called also roentgen ray

2

: a photograph obtained by use of X-rays

a chest X-ray

X-ray adjective