X-Ray
/ˈɛks reɪ/noun
A form of electromagnetic radiation with wavelengths shorter than ultraviolet, used for imaging and inspection.
Did you know?X-rays were named by Wilhelm Röntgen in 1895 because the new rays were unknown, and the “X” literally marked their mystery before science understood their power.
Etymological Timeline
Proto-Indo-European
PIE
*ḱes-
“to scrape, cut, or split”
Ancient Greek
Greek
xénos
“stranger, guest”
Late Latin
Latin
xystus
“a covered portico or garden walk”
19th Century
German
X-Strahlen
“X-rays, literally 'X-radiations'”
19th Century
English
X-ray
“the newly discovered penetrating rays”