Origin and Etymology of copperas
Middle English coperas, from Anglo-French coperose, from Medieval Latin cuprosa, probably from aqua cuprosa, literally, copper water, from Late Latin cuprum
First Known Use: 14th century
Medical Definition of copperas
: a green hydrated ferrous sulfate FeSO4·7H2O used especially in making inks and pigments—used especially of commercial grades not to be used internally
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