1. (noun)selenium, Se, atomic number 34 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) Synonyms: sou'-east, atomic number 34, selenium, southeast, southeastward
Synonyms and Antonyms of selenium 
