A sudden and quick electric current that flows between two objects at different electrical potentials caused by direct contact or which are induced by an electrostatic field.

Electric sparks play an important part in many physical effects; usually these are harmful and undesirable effects, ranging from the gradual destruction of contacts in a conventional electrical switch to the large-scale disruption resulting from lightning discharges.

Sometimes the spark is useful; for example, its function in the ignition system of an automobile, its use as an intense short-duration illumination source in high-speed photography, and its use as a source of excitation in spectroscopy.

1. The process of machining which is performed by electric sparks in a non-conductive liquid intervening substance.
2. A process by which materials that conduct electricity can be removed from a metal by an electric spark.

It is used to form holes with different shapes in materials that have poor machine operations.