ultraviolet

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

|Updated on: 21 Jun 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 hole allows in too much ultraviolet light, which contributes to higher temperatures.

— jen christensen, CNN, "Scientists lay out how to save a melting Antarctica -- and the grim future if we don't," 13 June 2018
The core then sends out x-rays and ultraviolet light that will cause that envelope of debris to shine for about 10,000 years, producing a nebula while the star’s core flickers off.

— jason daley, Smithsonian, "The Sun Will Produce a Beautiful Planetary Nebula When It Dies," 9 May 2018
Thick skin might also protect the body from the strong ultraviolet light at high altitudes.

— elizabeth pennisi, Science | AAAS, "Study of short Peruvians reveals new gene with a major impact on height," 16 May 2018
Our best guess is that the lower flux of ultraviolet radiation during the winter, along with the sun-blocking effect of the ring shadows on the winter hemisphere, reduces the production of the overlying haze.

— carolyn porco, Scientific American, "Cassini at Saturn: A Retrospective," 1 Oct. 2017
In the noisy, hot aluminum plants where workers wield vibrating hand tools and can be exposed to ultraviolet radiation, safety is paramount.

— michael c. bender, WSJ, "Why CEOs Have Such a Hard Time Moving Into Government," 14 Mar. 2018
The major risk factor for melanoma stems from exposure to ultraviolet rays, his post goes on to say, from either sunlight, tanning beds, or sun lamps.

— shari rudavsky, Indianapolis Star, "Surgeon general Jerome Adams' wife undergoing treatment for advanced skin cancer," 28 Mar. 2018
In a Facebook post, Adams outlined how exposure to ultraviolet rays from the sun or tanning beds can increase the likelihood of melanoma and described the warning signs.

— andrew joseph, STAT, "Surgeon general’s wife treated for melanoma recurrence as he highlights risks of tanning," 28 Mar. 2018
For contrast, arc eye is a burn: Welders get it from their exposure to bright ultraviolet light.

— susan crawford, WIRED, "What Are Screens Doing to Our Eyes—And Our Ability to See?," 27 Mar. 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