Similar term(s): potential, electromotive force, potential difference.
The difference in electrical charge between two points in a circuit expressed
in volts which makes electrical charges flow through a closed circuit.
One can compare this potential difference to water pressure. As there can
exist a pressure (difference in level for example) without an inevitable water
circulation, one can detect the electric potential without an inevitable
circulation of electrons : thus the terminal voltage of a plug is present if the
light is switched on or switched off.