Definition
copperahs
noun
- Plural of copperas; a green or blue-green crystalline compound of iron sulfate, historically used in dyeing, tanning, and ink production.
Usage: archaic; technical; chiefly historical
Examples
- Medieval dyers relied on copperahs to fix colors in wool and linen.
- The old recipe called for copperahs dissolved in water to create a mordant.
- Copperahs were mined and exported throughout Europe during the Renaissance.
- The blacksmith's workshop contained barrels of copperahs for treating metal surfaces.