Main Entry:

se·le·ni·um

Pronunciation:

\sə-ˈlē-nē-əm\

Function:

noun

Etymology:

New Latin, from Greek selēnē moon, from selas brightness

Date:

1818

: 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 element table