- A nonmetallic element of the sulphur group, and 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 78.9.
Definition
[ n.]