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 selenium in mushrooms also helps your body make antioxidants that prevent cell damage, Zumpano said, and the vitamin B6 helps your body make red blood cells and supports your central nervous system. —Maggie O'Neill, Verywell Health, 8 Mar. 2026

Stephanie Balais, an aspiring South Florida nursing student, died in 2018 at age 25 after receiving a lethal dose of the mineral selenium as an IV treatment for immune support. —Cindy Krischer Goodman, Sun Sentinel, 5 Mar. 2026

Another National Eczema Association Seal of Acceptance winner, this cream is made with thermal spring water that naturally contains the skin-soothing antioxidant selenium. —Sarah Felbin, Allure, 25 Feb. 2026

In addition to omega-3s, salmon is an excellent source of protein and vitamins and minerals such as potassium, B12, and selenium. —Jillian Kubala, Health, 19 Feb. 2026

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