Why is the ninth month called September?
ultraviolet ul·tra·vi·o·let (ŭl'trə-vī'ə-lĭt)
Abbr. UV, U.V.
Of or relating to the range of invisible radiation wavelengths from about 4 nanometers, on the border of the x-ray region, to about 380 nanometers, just beyond the violet in the visible spectrum. n.
Ultraviolet light or the ultraviolet part of the spectrum.
Adjective Relating to electromagnetic radiation having frequencies higher than those of visible light but lower than those of x-rays, approximately 1015-1016 hertz. Some animals, such as bees, are capable of seeing ultraviolet radiation invisible to the human eye. See more at electromagnetic spectrum.
Noun Ultraviolet light or the ultraviolet part of the spectrum. See Note at infrared.