selenium

noun

se·​le·​ni·​um sə-ˈlē-nē-əm 

: 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 serving size of 1 ounce exceeds the tolerable upper limit (UL) of selenium (the highest amount unlikely to pose a health risk). —Lana Barhum, Verywell Health, 8 Oct. 2025

Shrimp is packed with protein and is high in vitamins and minerals, like B12 and selenium. —Jillian Kubala, Health, 8 Oct. 2025

However, even high-quality 2D materials can have atomic defects, like missing sulfur or selenium atoms, which affect electrical behavior. —Bojan Stojkovski, Interesting Engineering, 14 Sep. 2025

Nutritional yeast Nutritional yeast is rich in B vitamins, essential amino acids, and vitamins such as selenium, phosphorus, and magnesium. —Alessandra Signorelli, Vogue, 12 Sep. 2025

Word History

Etymology

New Latin, from Greek selēnē moon, from selas brightness

First Known Use

1818, in the meaning defined above

Phrases Containing selenium

• selenium cell

Rhymes for selenium

• asplenium
• delphinium
• perineum
• proscenium
• ruthenium
• vaccinium
• rhenium

Kids Definition

selenium

noun

se·​le·​ni·​um sə-ˈlē-nē-əm 

: 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 

: 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