/ Dictionary / Index X x-ray: Meaning and Definition of Find definitions for: x-ray Pronunciation: (eks'rā"), [key] — n. Often,x-rays.a form of electromagnetic radiation, similar to light but of shorter wavelength and capable of penetrating solids and of ionizing gases. such radiation having wavelengths in the range of approximately 0.1–10 nm. a radiograph made by x-rays. (cap.) a word in communications to represent the letter X. —v.t. to examine, photograph, or treat with x-rays. —adj. of or pertaining to x-rays. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: x-ray (Thesaurus) X-rated x-ray astronomy Related Content Daily Word Quiz: diligent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language