sulfur UK /ˈsʌl.fə/US /ˈsʌl.fɚ/noun 4adjective 2verb 1forms 5 noun4 •A chemical element with atomic number 16, having a bright yellow color and characteristic smell, used commercially in a variety of products such as insecticides, black powder, and matchsticks.It went like this: first, we were cavemen, then there was ancient Greece, then Rome burned (cue sulfur-odor FX), then there was the Great Depression, and, finally, we reached the modern age. — 2003 •The element symbolically associated with hellfire or damnation, or in alchemy, the fiery principle present in all things.“She shall be blasted like a riven oak! Drowned in sulphur! Torn by whirlwinds!” — 1970 •A yellowish green colour, like that of sulfur. •Any of various pierid butterflies of the subfamily Coliadinae, especially the sulfur-coloured species. adjective2 •Of a yellowish green colour, like that of sulfur. •Having a characteristic sulfur-like smell, reminiscent of rotten eggs. verb1 •To treat with sulfur, or a sulfur compound, especially to preserve or to counter agricultural pests. formssulfured · sulfuring · sulfurs · more sulfur · most sulfur