Dictionary.com
definitions

copper sulphate

noun
  1. a copper salt found naturally as chalcanthite and made by the action of sulphuric acid on copper oxide. It usually exists as blue crystals of the pentahydrate that form a white anhydrous powder when heated: used as a mordant, in electroplating, and in plant sprays. Formula: CuSO 4
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

Examples from the Web for copper sulphate

Historical Examples of copper sulphate