selenium

[ si-lee-nee-uhm ]

noun

, Chemistry.

1. a nonmetallic element chemically resembling sulfur and tellurium, occurring in several allotropic forms, as crystalline and amorphous, and having an electrical resistance that varies under the influence of light. : Se; : 78.96; : 34; : (gray) 4.80 at 25°C, (red) 4.50 at 25°C.

selenium

/ sɪˈliːnɪəm /

noun

1. a nonmetallic element that exists in several allotropic forms. It occurs free in volcanic areas and in sulphide ores, esp pyrite. The common form is a grey crystalline solid that is photoconductive, photovoltaic, and semiconducting: used in photocells, solar cells, and in xerography. Symbol: Se; atomic no: 34; atomic wt: 78.96; valency: –2, 4, or 6; relative density: 4.79 (grey); melting pt: 221°C (grey); boiling pt: 685°C (grey)

selenium

/ sĭ-lē′nē-əm /

1. A nonmetallic element that occurs in a gray crystalline form, as a red powder, or as a black glassy material. It is highly photosensitive and can be used to convert light into electricity. Its ability to conduct electricity also increases with higher exposure to light. For these reasons selenium is used in photocopying technology, photography, and solar cells. Atomic number 34; atomic weight 78.96; melting point 217°C; boiling point 684.9°C; specific gravity (gray) 4.79; (red) 4.5; (black) 4.28; valence 2, 4, or 6.
2. See Periodic Table

Word History and Origins

Origin of selenium¹

< New Latin (1818) < Greek selḗn ( ē ) moon + New Latin -ium -ium; named in allusion to its similarity to tellurium

Word History and Origins

Origin of selenium¹

C19: from New Latin, from Greek selēnē moon; named by analogy to tellurium (from Latin tellus earth)

Example Sentences

"We believe our method will generalize to other materials, such as tin, selenium, tellurium and related alloys with low melting points, and it could be interesting to explore for future flexible electronic circuits."

From Science Daily

Others have found that using dandruff shampoo, especially Selsun Blue with selenium sulfide, can be helpful.

From Seattle Times

Kombu is also an unassuming health boost; as noted by Dr. Josh Axe with Dr. Axe, it "offers tons of minerals, such as calcium, copper, iron, magnesium, manganese, molybdenum, phosphorus, potassium, selenium, vanadium and zinc."

From Salon

In the UK, 71% of adults have insufficient vitamin D in winter, and teenage girls and women often have deficiencies of iodine, selenium and iron.

From Science Daily

And it turns out that when they go to areas with more copper and selenium in the ground, they have more calves.

From Science Daily