(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.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). copperas. Retrieved September 23, 2026, from http://smartdefine.org/copperas/definitions/1991481 |
| Chicago | Webster's. 2011. "copperas" http://smartdefine.org/copperas/definitions/1991481 (accessed September 23, 2026). |
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| MLA | Webster's. "copperas" 27 May 2011. Web. 23 September 2026. <http://smartdefine.org/copperas/definitions/1991481> |