sulfur
Cross references: 1. element 1. sul.fur or sul.phur \'s*l-f*r\ n [ME sulphur brimstone, fr. L sulpur, sulphur, sulfur] 1: a nonmetallic element that occurs either free or combined esp. in sulfid es and sulfates, is a constituent of proteins, exists in several allotropic forms including yellow orthorhombic crystals, resembles oxygen chemically but is less active and more acidic, and is used esp. in the chemical and paper industries, in rubber vulcanization, and in medicine for treating skin diseases 2: something that suggests sulfur 2. sulfur \-f(*-)rin\ vt or sul.fur.ing : to treat with sulfur or a sulfur compound
Webster's English Dictionary