Reduction potential
Measure of the tendency of a substance to gain or lose electrons
Redox potential (also known as oxidation / reduction potential, ORP, pe, E r e d {\displaystyle E_{red}} , or E h {\displaystyle E_{h}}) is a measure of the tendency of a chemical species to acquire electrons from, or lose electrons to, an electrode and thereby be reduced or oxidised respectively. Redox potential is expressed in volts (V). Each species has its own intrinsic redox potential; for example, the more positive the reduction potential (reduction potential is more commonly used due to the general formalism in electrochemistry), the greater the species' affinity for electrons and its tendency to be reduced (stronger oxidising agent).
From Wikipedia, under CC BY-SA. More on occurri.