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

For example, some shampoos contain selenium sulfide or pyrithione zinc to treat yeast overgrowth, while others contain ketoconazole. —Petra Guglielmetti, Glamour, 27 May 2026

Seitan also contains nutrients like selenium, iron, calcium, and phosphorus. —Lauren Panoff, Verywell Health, 17 May 2026

In addition to protein and antioxidants, sunflower seeds contain B vitamins and minerals like magnesium, selenium, copper, zinc, iron, and potassium, says Umo Callins, MS, RD, CSSD, LD, CPT. —Alessandra Signorelli, Vogue, 12 May 2026

Diets high in antioxidants such as vitamins C and E, zinc and selenium may also be helpful in protecting sperm from oxidative stress, which can damage cells and reduce count. —Daryl Austin, USA Today, 2 May 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

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

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