DICT.TW Dictionary Taiwan

 Cop·per·as n.  Green vitriol, or sulphate of iron; a green crystalline substance, of an astringent taste, used in making ink, in dyeing black, as a tonic in medicine, etc. It is made on a large scale by the oxidation of iron pyrites. Called also ferrous sulphate.
 Note: ☞ The term copperas was formerly synonymous with vitriol, and included the green, blue, and white vitriols, or the sulphates of iron, copper, and zinc.
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