from The American Heritage® Dictionary of the English Language, 4th Edition

  • adj. 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • adj. of electromagnetic radiation beyond (higher in frequency than) light visible to the human eye; radiation with wavelengths from 380 nanometre - 10 nanometre
  • n. Ultraviolet colour.

from the GNU version of the Collaborative International Dictionary of English

  • adj. Lying outside the visible spectrum at its blue-violet end; -- said of light more refrangible (i. e. having a shorter wavelength) than the extreme violet rays of the visible spectrum. Electromagnetic radiation with wavelengths shorter than those of ultrviolet light are not usually considered as light waves, but are classified differently. The ultraviolet region of the electromagnetic spectrum is generally considered as comprising those electromagnetic emissions with wavelengths lying between those of visible light and those of X-rays, i. e. between 4000 Angstroms and 100 Angstroms.

from The Century Dictionary and Cyclopedia

  • Beyond the violet: used of the invisible rays of the spectrum which are more refrangible than the violet, and consequently lie beyond them. See spectrum.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • adj. having or employing wavelengths shorter than light but longer than X-rays; lying outside the visible spectrum at its violet end
  • n. radiation lying in the ultraviolet range; wave lengths shorter than light but longer than X rays


from Wiktionary, Creative Commons Attribution/Share-Alike License

ultra- +‎ violet


  • The Restore Clean Water System from HoMedics claims that its built-in ultraviolet lights will kill 99. 9999% of bacteria, 99.99% of viruses and 99.95% of microbial cysts in your drinking water.

    A UV Water Pitcher Kills 99.999% of Germs in Drinking Water | Impact Lab

  • Paget, investigated the significance of a green fluorescence visible in ultraviolet light which pointed to adrenaline in the presence of O2, and alkali, and found that this appears to a high degree specific for adrenaline.

    Otto Loewi - Nobel Lecture

  • The band from 0.1 to 0.4 micrometers is called ultraviolet radiation.

    Electromagnetic radiation

  • The ultraviolet “rays” are not visible; thus it is incorrect to call ultraviolet energy ultraviolet “light.”

    The New Super-Nutrition

  • Ultraviolet light, also called ultraviolet radiation or UV, is a portion of the electromagnetic spectrum between x-rays and visibility light.

    eHow - Health How To's

  • "Glass is almost perfectly opaque to deep ultraviolet, which is why it's hard to get a tan through a window," e-mails physicist

    The Globe and Mail - Technology RSS feed

  • It's that pesky, invisible specter called ultraviolet light.

    HowStuffWorks Daily Feed

  • Miller, working in his laboratory at the University of Chicago, demonstrated that when exposed to an energy source such as ultraviolet radiation, these compounds and water can react to produce amino acids essential for the formation of living matter.

    Waldo Jaquith - Inorganic dust can have lifelike properties.

  • Dr. Francisco Delgado, an internal medicine/infections disease specialist trained in the US at Vanderbilt U and a member of all the best medical societies, with all the credentials he could possibly have (a diplomate and fellow in the appropriate internal medicine groups), recommends both a filtration system and a second system, such as ultraviolet light or silver colloid treatment.

    Colloidal Silver Water Purification

  • As one who came down with amoebas somehow, someplace, in San Miguel, I can say that my physician insists on a two-stage water purification system, both a good filtration system and then something else, such as ultraviolet light or the silver cartridge system.

    no such thing as city water?


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  • Adds a entire new meaning to rose-colored cataracts. It is plum crazy as plumbago. Way-to-glow!

    April 25, 2013

  • "An illustration of how ultraviolet appears is provided by the Impressionist painter Claude Monet. Following cataract surgery in 1923, his colour palette changed significantly; after the operation he painted water lilies with more blue than before. This may be because after lens removal he could see ultraviolet light, which would have given a blue cast to the world."


    April 24, 2013