Reference Electrode : A standard cell of known voltage used for making voltage measurements of a corrosion cell. Calomel and copper sulfate are common reference electrodes. (COGWE, SSWID)
The Mudblogger (Oilfield, Energy and Related Photographs), Oil Field Glossary, TX, USA 2014. http://mudblogger.com/oilfield-glossary/, (Oil - Amer) {777}