a nonmetallic element occurring naturally in large quantities, either combined as in the sulphides (as pyrites) and sulphates (as gypsum), or native in volcanic regions, in vast beds mixed with gypsum and various earthy materials, from which it is melted out. symbol s. atomic weight 32. the specific gravity of ordinary octohedral sulphur is 2.05; of prismatic sulphur, 1.96.-any one of numerous species of yellow or orange butterflies of the subfamily pierinae; as, the clouded sulphur (eurymus, / colias, philodice), which is the common yellow butterfly of the eastern united states.