[kop-er-uh s]

noun Chemistry.

Origin of copperas

1400–50; late Middle English coperas, variant of Middle English coperose < Medieval Latin (aqua) cuprōsa copperish (water). See copper1, -ose1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for copperas

Historical Examples of copperas

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

  • 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



a less common name for ferrous sulphate

Word Origin for copperas

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