chlorine /ˈkloɚˌiːn/ noun Learner's definition of CHLORINE
[noncount]
: a chemical that in its natural form is a greenish-yellow gas and has a strong smell氯 ◊ Chlorine in a liquid or solid form is often added to water (such as the water in a swimming pool) to keep it clean.人们常常把液态或固态氯加入水中（如游泳池）以保持水的清洁。