beyond the violet in the spectrum, corresponding to light having wavelengths shorter than 4000 angstrom units.
pertaining to, producing, or utilizing light having such wavelengths: an ultraviolet lamp.


ultraviolet radiation.

Compare infrared.

Origin of ultraviolet

First recorded in 1870–75; ultra- + violet
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for ultraviolet

Contemporary Examples of ultraviolet

Historical Examples of ultraviolet

  • As they sat down, he aimed his ultraviolet light-pencil at a serving robot.

    Space Viking

    Henry Beam Piper

  • The right pan camera filters are mainly longer wavelength in the ultraviolet range.

  • Wounds are treated effectively and water is sterilized by the ultraviolet radiant energy in modern artificial illuminants.

    Artificial Light

    M. Luckiesh

  • The ultraviolet rays falling upon this screen were transformed into visible rays by the phenomenon of fluorescence.

    Artificial Light

    M. Luckiesh

  • In most of the vats vegetation grew in various stages, greening under the ultraviolet rays that radiated from the low roof.

    Rebels of the Red Planet

    Charles Louis Fontenay

British Dictionary definitions for ultraviolet



the part of the electromagnetic spectrum with wavelengths shorter than light but longer than X-rays; in the range 0.4 × 10 –6 and 1 × 10 –8 metres


of, relating to, or consisting of radiation lying in the ultravioletultraviolet radiation Abbreviation: UV
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for ultraviolet

"beyond the violet end of the visible spectrum," 1840, from ultra- + violet. Ultra-red (1870) was a former name for what now is called infra-red.

Online Etymology Dictionary, © 2010 Douglas Harper

ultraviolet in Medicine




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.


Ultraviolet light or the ultraviolet part of the spectrum.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

ultraviolet in Science




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.


Ultraviolet light or the ultraviolet part of the spectrum. See Note at infrared.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.