/eks"ray'/ , n. Also, x ray, X ray .
1. Physics.
a. Often, x-rays . a form of electromagnetic radiation, similar to light but of shorter wavelength and capable of penetrating solids and of ionizing gases.
b. such radiation having wavelengths in the range of approximately 0.1-10 nm.
2. a radiograph made by x-rays.
3. ( cap. ) a word in communications to represent the letter X.
v.t.
4. to examine, photograph, or treat with x-rays.
adj.
5. of or pertaining to x-rays.
Also, X-ray .
[ 1895-1900; trans. of G X-Strahl (1895), the name orig. given to the rays by Röntgen, their discoverer, x signifying their unknown nature ]