The story
Etymology from Wiktionary, CC BY-SA 4.0.
x unit
Today it means: A unit of length (symbol xu) approximately equal to 0.1 picometres, used to quote the wavelength of X-rays and gamma rays. Full definition →
Today it means: A unit of length (symbol xu) approximately equal to 0.1 picometres, used to quote the wavelength of X-rays and gamma rays. Full definition →
Etymology from Wiktionary, CC BY-SA 4.0.