selenium

noun

se·​le·​ni·​um sə-ˈlē-nē-əm How to pronounce selenium (audio)
: 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
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
For example, some shampoos contain selenium sulfide or pyrithione zinc to treat yeast overgrowth, while others contain ketoconazole. — Petra Guglielmetti, Glamour, 27 May 2026 Like other fatty fish, salmon is rich in protein, omega-3 fatty acids, vitamin B12, and selenium, among other nutrients. — Mark Gurarie, Health, 25 June 2026 Garlic offers more vitamin and minerals, including more vitamin C and selenium. — Heather Jones, Verywell Health, 4 July 2026 Wild salmon, for example, contains proteins, vitamins A, D and B-12, and critical minerals such as selenium and potassium — as well as high-quality omega-3s. — Sandee Lamotte, CNN Money, 18 June 2026 See All Example Sentences for selenium

Word History

Etymology

New Latin, from Greek selēnē moon, from selas brightness

First Known Use

1818, in the meaning defined above

Time Traveler
The first known use of selenium was in 1818

Phrases Containing selenium

Rhymes for selenium

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Browse Nearby Words

selenitic
selenium
selenium cell
See all Nearby Words

Cite this Entry

“Selenium.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/selenium. Accessed 7 Jul. 2026.

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Kids Definition

selenium

noun
se·​le·​ni·​um sə-ˈlē-nē-əm How to pronounce selenium (audio)
: an element that is sensitive to light and is used especially in glass, alloys, and electronic devices see element

Medical Definition

selenium

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

Britannica.com: Encyclopedia article about selenium

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