se·​le·​ni·​um | \ sə-ˈlē-nē-əm How to pronounce selenium (audio) \

Definition of selenium

: a photosensitive element that occurs in both crystalline and amorphous forms, is obtained chiefly as a by-product in copper refining, and is used especially in glass, semiconductor devices, and alloys — see Chemical Elements Table

Examples of selenium in a Sentence

Recent Examples on the Web The reactions at the selenium electrode appeared to start in the molten salt before finishing up on the electrode surface. John Timmer, Ars Technica, 24 Aug. 2022 Unlike some of the others on this list, this maximum-strength dandruff shampoo uses the antifungal selenium sulfide as its anti-dandruff ingredient. Anthea Levi,, 24 Sep. 2021 Saute frozen spinach or blend it into a smoothie for C, E, and selenium. Melanie Curry, Men's Health, 15 Aug. 2022 As a result, the topsoil contained elevated levels of uranium and selenium. Mark Olalde, ProPublica, 8 Aug. 2022 These include calcium, magnesium, vitamin E, vitamin D, several B vitamins, vitamin A, vitamin K, potassium, iodine, selenium, borate, zinc, manganese, molybdenum, beta-carotene, and iron. Allure, 25 Apr. 2022 Many are already winding up in landfills, where components that contain toxic heavy metals such as selenium and cadmium can contaminate groundwater. Rachel Kisela, Los Angeles Times, 14 July 2022 The review examined the impacts of popular supplements like beta carotene, folic acid, calcium, magnesium, selenium and zinc, as well as multivitamins and vitamins A, B, C, D and E. Aria Bendix, NBC News, 21 June 2022 The range was pretty high, from less than a year for gallium and selenium to nearly 200 years for gold. John Timmer, Ars Technica, 20 May 2022 See More

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

First Known Use of selenium

1818, in the meaning defined above

History and Etymology for selenium

New Latin, from Greek selēnē moon, from selas brightness

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Time Traveler for selenium

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The first known use of selenium was in 1818

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Dictionary Entries Near selenium



selenium cell

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Statistics for selenium

Last Updated

6 Sep 2022

Cite this Entry

“Selenium.” Dictionary, Merriam-Webster, Accessed 28 Sep. 2022.

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More Definitions for selenium


se·​le·​ni·​um | \ sə-ˈlē-nē-əm How to pronounce selenium (audio) \

Kids Definition of selenium

: a gray powdery chemical element used chiefly in electronic devices


se·​le·​ni·​um | \ sə-ˈlē-nē-əm How to pronounce selenium (audio) \

Medical Definition of selenium

: a nonmetallic photosensitive element that occurs in both crystalline and amorphous forms, is an essential trace element found especially in grains and meat, and is used chiefly in glass, semiconductor devices, and alloys symbol Se — see Chemical Elements Table, selenosis

More from Merriam-Webster on selenium

Nglish: Translation of selenium for Spanish Speakers Encyclopedia article about selenium


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