A nonmetallic chemical element (symbol Se) with an atomic number of 34, used mainly in glassmaking and pigments and as a semiconductor. / A single atom of this element.

plural of selenium

(astronomy, historical) A device consisting of a closeable ball of blackened wood surrounding a glass lens that focuses light onto a selenium cell attached to a galvanometer; used by astronomers to measure the light variations of a heavenly body.

plural of selenium eye

a photoelectric cell that uses a strip of selenium as the electron source

A material, produced by fermentation of Saccharomyces cerevisiae in the presence of selenium, that has selenium atoms incorporated into the amino acid methionine

(inorganic chemistry) The binary compound of selenium and fluorine SeF₆.

plural of selenium yeast