Selenium
WordNet
noun
(1) A toxic nonmetallic element related to sulfur and tellurium; occurs in several allotropic forms; a stable grey metallike allotrope conducts electricity better in the light than in the dark and is used in photocells; occurs in sulfide ores (as pyrite)
WiktionaryText
Etymology
A word derived by Swedish chemist Berzelius in 1818, from Σελήνη (selēnē, "moon").
Noun
- a nonmetallic chemical element (symbol Se) with an atomic number of 34.