selenium

• POS: Noun
• HYPHEN: se=le=ni=um

CIDE DICTIONARY

selenium, n. [NL., from Gr. selh`nh the moon. So called because of its chemical analogy to tellurium (from L. tellus the earth), being, as it were, a companion to it.].

 A nonmetallic element of the sulphur group of atomic number 34, analogous to sulphur in its compounds. It is found in small quantities with sulphur and some sulphur ores, and obtained in the free state as a dark reddish powder or crystalline mass, or as a dark metallic-looking substance. It exhibits under the action of light a remarkable variation in electric conductivity, and is used in certain electric apparatus. Symbol Se. Atomic weight 78.96.  [1913 Webster]

OXFORD DICTIONARY

selenium, n. Chem. a non-metallic element occurring naturally in various metallic sulphide ores and characterized by the variation of its electrical resistivity with intensity of illumination.

Idiom

selenium cell a piece of this used as a photoelectric device.

Usage

Symb.: Se.

Derivative

selenate n. selenic adj. selenious adj.

Etymology

mod.L f. Gk selene moon + -IUM