The amount of energy required to move an electron across a potential difference of one volt. A common unit of energy in physics.

a unit of energy defined by the change in potential energy of an electron traveling across a potential difference of 1 volt

Energy unit used as the basis of measurement for atomic (eV), electronic (keV), nuclear (MeV), and subnuclear processes (GeV or TeV). One electron-volt is equal to the amount of energy gained by an electron dropping through a potential difference of one volt, which is 1.6 ´ 10- 19 joules.