ultraviolet

adjective ul·tra·vi·o·let \ ˌəl-trə-ˈvī-(ə-)lət \

|Updated on: 16 Aug 2018

Definition of ultraviolet

1 : situated beyond the visible spectrum at its violet end —used of radiation having a wavelength shorter than wavelengths of visible light and longer than those of X-rays

2 : relating to, producing, or employing ultraviolet radiation

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ultraviolet

noun

See ultraviolet defined for English-language learners

See ultraviolet defined for kids

Recent Examples of ultraviolet from the Web

The key components to this new method of detection are an ordinary smartphone, some special software downloaded onto the phone, a box made from Lego bricks, ultraviolet light, a standard 96-well test plate– and a special sauce, so to speak.

— allison barrie, Fox News, "Innovative project harnesses Legos and smartphones in the fight against invisible, deadly weapons," 13 July 2018
Free radicals are created by environmental pollutants and ultraviolet radiation.

— talia abbas, SELF, "I Had a Dermatologist Critique My Skin-Care Routine—and Here's What I'm Changing," 20 June 2018
Methane is also quickly broken down by ultraviolet radiation, so any of the gas discovered on Mars was probably released recently.

— adam mann, Scientific American, "Curiosity Rover Uncovers Long-Sought Organic Materials on Martian Surface," 7 June 2018
Because ultraviolet radiation and oxidizing compounds in the martian soil would destroy any compounds exposed at the surface, Curiosity's scientists used a robotic drill to penetrate several centimeters into the mudstone.

— paul voosen, Science | AAAS, "NASA rover hits organic pay dirt on Mars," 7 June 2018
Meanwhile, stricter approval standards in the U.S. have brought innovation to a standstill and limited options to defend against the sun's harmful ultraviolet radiation.

— jack kaskey, chicagotribune.com, "Your outdated sunscreen exposes you to needless cancer risk," 30 May 2018
The sun emits two types of ultraviolet radiation that reach the Earth: UVA and UVB, both of which damage DNA in the skin.

— dr. melina jampolis, CNN, "Aging gracefully: Tightening your skin safely and effectively," 16 May 2018
Chromium also absorbs ultraviolet wavelengths of light, but re-emits some of it at a lower energy in the red wavelengths.

— c. claiborne ray, New York Times, "From One Mineral, Brilliant Reds and Bright Blues," 22 June 2018
Grinspoon is especially intrigued by Venusian clouds that sometimes display unexplained markings of dark, ultraviolet-absorbing particles.

— NBC News, "NASA has a plan to let humans soar above the clouds on Venus," 5 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'ultraviolet.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of ultraviolet

1840

in the meaning defined at sense 1

See Words from the same year

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ULTRAVIOLET Defined for English Language Learners

ultraviolet

adjective

Definition of ultraviolet for English Language Learners

—used to describe rays of light that cannot be seen and that are slightly shorter than the rays of violet light

ULTRAVIOLET Defined for Kids

ultraviolet

adjective ul·tra·vi·o·let \ ˌəl-trə-ˈvī-ə-lət \

Definition of ultraviolet for Students

: relating to, producing, or being energy that is like light but has a slightly shorter wavelength and lies beyond the violet end of the spectrum

Medical Dictionary

ultraviolet

adjective ul·tra·vi·o·let \ ˌəl-trə-ˈvī-(ə-)lət \

medical Definition of ultraviolet

1 : situated beyond the visible spectrum at its violet end —used of radiation having a wavelength shorter than wavelengths of visible light and longer than those of X-rays

2 : relating to, producing, or employing ultraviolet radiation