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copperas

[kop-er-uh s]
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noun Chemistry.
  1. ferrous sulfate.
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Origin of copperas

1400–50; late Middle English coperas, variant of Middle English coperose < Medieval Latin (aqua) cuprōsa copperish (water). See copper1, -ose1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for copperas

Historical Examples

  • It was black, but the copperas would eat the paper after a while.

    The Story of Young Abraham Lincoln

    Wayne Whipple

  • Alum and copperas have been known in the Highlands long ages.

    Vegetable Dyes

    Ethel M. Mairet

  • Put the wool into this for 1/2 hour; then return it into the alum and copperas for 10 to 15 minutes.

    Vegetable Dyes

    Ethel M. Mairet

  • We're goin' up to Copperas Creek and there ain't a thing in that.

    Mitch Miller

    Edgar Lee Masters

  • The amount of copperas should be from one and a half to twice that of the indigo.

British Dictionary definitions for copperas

copperas

noun
  1. a less common name for ferrous sulphate
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Word Origin

C14: coperose, via Old French from Medieval Latin cuperosa, perhaps originally in the phrase aqua cuprosa copper water
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012