chloasma Syllabification: (chlo·as·ma)Pronunciation: /klōˈazmə/Definition of chloasma noun a temporary condition, typically caused by hormonal changes, in which large brown patches form on the skin, mainly on the face. Origin: mid 19th century: from Greek khloazein 'become green'chloasma in other Oxford dictionaries Definition of chloasma in the British & World English dictionary