ultraviolet

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

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

Still, ultraviolet rays, which can have a long-term effect on eyesight, come at the eyes.

— sarah freishtat, Aurora Beacon-News, "Some Fox Valley schools to keep students inside during eclipse," 18 Aug. 2017
The disruption led to a weakening of the potency of a enzyme that blocks the sun's harmful ultraviolet radiation, thus allowing the skin to sustain more damage.

— sarah kinonen, Allure, "What Late-Night Eating May Do to Your Level of Sun Protection," 18 Aug. 2017
Even though a portion of the sun will be covered, experts say this amount of ultraviolet light is still dangerous.

— nicholas rondinone, courant.com, "You Can't Just Stare At The Partial Eclipse Without Eye Protection," 17 Aug. 2017
Currently, that uses ultraviolet light with a wavelength of 193nm.

— peter bright, Ars Technica, "Intel’s next generation chip plans: Ice Lake and a slow 10nm transition," 15 Aug. 2017
This is false, as science has proven that sunscreen is the only known antidote to skin cancer caused by ultraviolet light.

— kathleen hou, The Cut, "Lululemon Totes Are Spreading Questionable Sunscreen Facts," 8 Aug. 2017
There is strong evidence that some bacteria can survive strong ultraviolet light from the sun and other space radiation.

— dave brody executive producer, Fox News, "Why kill Cassini? Saturn probe's fate carefully considered," 19 July 2017
Deep inside their tissue are little proteins that take the sun’s ultraviolet light and turn it into a glowing green sunscreen, shielding from the sun these corals that live just below the water’s surface.

— joanna klein, New York Times, "In the Deep, Dark Sea, Corals Create Their Own Sunshine," 7 July 2017
As Ian Sample at The Guardian reports, a new study suggests that in the presence of ultraviolet light, perchlorates, a class of chemical compounds widespread on Mars' surface, turn deadly for bacteria.

— jason daley, Smithsonian, "Mars Surface May Be Too Toxic For Microbial Life," 7 July 2017

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

ULTRAVIOLET Defined for English Language Learners

ultraviolet

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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

play

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

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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