(physics) The major stable isotope of sulfur, ³²₁₆S, having sixteen protons and sixteen neutrons; it amounts to 95% of the element in nature

(physics) A minor stable isotope of sulfur, ³⁴₁₆S, having sixteen protons and eighteen neutrons; it amounts to about 4% of the element in nature

(physics) A minor stable isotope of sulfur, ³⁶₁₆S, having sixteen protons and twenty neutrons; it amounts to only 0.01% of the element in nature

(physics) A minor stable isotope of sulfur, ³³₁₆S, having sixteen protons and seventeen neutrons; it amounts to less than 1% of the element in nature

(chemistry) a simple binary compound of sulfur and nitrogen, S₄N₄, having a ring structure; it is explosive / (chemistry) an inorganic polymer, [SN]ₙ, that has metallic properties

(inorganic chemistry) The weak acid, H₂SO₃, present in a solution of sulfur dioxide in water; it is a reducing agent and mild bleach.

(technical) Mustard gas.

(American spelling, inorganic chemistry) A toxic gas, of molecular formula SO₂ that is found in the emissions of volcanos and those of burning coal or petroleum; dissolves in water to form sulfurous acid and, in the presence of oxygen, sulfuric acid, and is thus responsible for acid rain.

(inorganic chemistry) A corrosive liquid, SO₃, which forms sulfuric acid on contact with water; made commercially by the oxidation of sulfur dioxide.

(American spelling) A candle-shaped device that emits sulfur dioxide when burnt; used to fumigate rooms