n 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)
n the compass point midway between south and east; at 135 degrees
[计] 栈空, 系统扩充
[医] 硒(34号元素)