se·​le·​ni·​um | \sə-ˈlē-nē-əm \

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

Burning coal creates ash that can contain arsenic, selenium, lead and mercury. Jon Kamp, WSJ, "South Carolina Faces More Flooding as Rivers Continue to Crest," 25 Sep. 2018 Among the more than two dozen ingredients in the kangaroo formula: biotin, choline, inositol, calcium, phosphorus, potassium, sodium, magnesium, zinc, iron, manganese, copper, iodine and selenium. Serena Solomon, New York Times, "Saving Koalas, and Other Marsupials, With Milk Almost as Good as Mom’s," 24 Feb. 2018 As if the asbestos findings aren't scary enough, the lab also found the heavy metals barium, chromium, selenium and lead in Just Shine Shimmer Powder. Marci Robin, Good Housekeeping, "UPDATE: Justice Has Just Announced a Recall of 8 Makeup Products Due to Asbestos Concerns," 1 Feb. 2018 Important nutrients in mushrooms include selenium, vitamin D, glutathione and ergothioneine. Robert Beelman, CNN, "The humble mushroom is the newest superfood," 25 Apr. 2018 Collingwood also cites micronutrient deficiencies in B vitamins, iron, magnesium, selenium and potassium as a potential pitfall of keto eating, along with a chance of ketoacidosis. Katie Parsons,, "Ketogenic diet popular for weight loss," 13 June 2018 Lead, arsenic, boron, cadmium, chromium, cobalt, copper, lead, mercury, molybdenum, selenium, thallium, and uranium are among the chemicals and heavy metals listed with coal ash deposits. Grace Schneider, The Courier-Journal, "An Indiana county is paying a steep price for burying toxic coal ash," 18 May 2018 What bicarbonates do—selenium, magnesium, sodium, things of that nature—is help the water get into the muscle and hydrate it. Clay Skipper, GQ, "The Trainer to LeBron James and Victor Oladipo Shares the Recovery Secrets of NBA Stars," 31 May 2018 Unfortunately celiac disease is already known to cause deficiencies in zinc, selenium and folic acid, so those who are pregnant and suffering from the disease need to pay special attention to these three vitamins. Hannah Drown,, "How do celiac disease and gluten-free diets impact pregnancy?," 8 May 2018

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.

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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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Statistics for selenium

Last Updated

13 Nov 2018

Look-up Popularity

Time Traveler for selenium

The first known use of selenium was in 1818

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More Definitions for selenium



English Language Learners Definition of selenium

: a chemical element that is used in electronic devices to make them sensitive to light


se·​le·​ni·​um | \sə-ˈlē-nē-əm \

Kids Definition of selenium

: a gray powdery chemical element used chiefly in electronic devices


se·​le·​ni·​um | \sə-ˈlē-nē-əm \

Medical Definition of selenium 

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

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by force of circumstances

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