A luminous discharge of current that is formed when a strong current jumps a gap in a circuit or between two electrodes.
An electric current, often strong, brief, and luminous, in which electrons jump across a gap. Electric arcs across specially designed electrodes can produce very high heats and bright light, and are used for such purposes as welding and illumination in spotlights. Unwanted arcs in electrical circuits can cause fires. Lightning is a case of an electric arc between one cloud and the earth or another cloud, as are sparks caused by discharges of static electricity.