a gas that stings (= causes sharp pain in) the eyes, producing tears and making it difficult to breathe. CS gas is sometimes used to control crowds. 催泪性毒气（或瓦斯） Word Origin1960s: from the initials of Ben B. Corson (1896–1987) and Roger W. Stoughton (1906–57), the American chemists who discovered the properties of the chemical in 1928.