Electromagnetic radiation of shorter wavelength than visible radiation; roughly, radiation in the wavelength interval from 100 to 4000 angstroms. Also called ultraviolet or ultraviolet radiation. See X-ray.
Ultraviolet radiation from the sun is responsible for many complex photochemical reactions characteristic of the upper atmosphere; e.g., the formation of the ozone layer through ultraviolet dissociation of oxygen molecules followed by recombination to form ozone.
This article is based on NASA's Dictionary of Technical Terms for Aerospace Use