[mass noun](Chemistry)a colourless astringent compound which is a hydrated double sulphate of aluminium and potassium, used in solution in dyeing and tanning (化)明矾
Chem. formula: AlK(SO4)2•12H2O 化学分子式: AlK(SO4)212H2O ■[count noun]any of a number of analogous crystalline double sulphates of a monovalent metal (or group) and a trivalent metal 二硫酸盐类
语源
late Middle English : via Old French from Latin alumen, alumin- related to aluta 'tawed leather'