Definition of: sulfur

(sul′fər) noun
1. A chemically active, nonmetallic element (symbol S, atomic number 16), under usual conditions consisting of pale yellow crystals but known in many other allotropic forms, and representing an essential constituent of living organisms. See lisiting under PERIODIC TABLE.
2. Any of various yellowish pieridine butterflies, as the common North American clouded sulfur (Colias philodice) or the cloudless sulfur (Callidryas eubule).
—flowers of sulfur A fine yellow powder obtained by the distillation of sulfur.
—v.t. To treat or fume, as a wine cask or a hive, with sulfur or with sulfurous acid. Also sul′phur. [<AF sulfre, OF soufre <L sulfur, -uris]