This entry outlines the various electrode configurations for electrical arc discharges ranging from the normal arc discharge, the low-voltage arc discharge, low-current arc discharge, among many others. It provides an insight into the typical parameters that characterize the arc discharge and conclude with some applications of the arc discharge in relation to the various industrial sectors. Arc discharges can be ignited at subatmosphere up to hundreds of atmospheres depending on the field of application. Arc discharges generated at high current (>>10 A) are very common; however, low current (<1 A) are more rare. This makes arc discharges to be characterized by a wide variety of forms even with reference to the value of the potential difference between the electrodes, the plasma densities, as well as the power source, which may be AC or DC. Arc discharges have been used in wide areas of application, some of which includes the metallurgical area such as smelting of metals in arc furnaces as well as electric welding. The synthesis of carbon nanotubes is one of the applications of the arc discharges aside from its application in plasma generators and charged particle sources. Arc discharges at high pressure have been used in arc heaters and underwater welding, for the synthesis of hydrocarbons and fluorocarbons, as well as for the generation of syngas for application of waste-to-energy processes. It is a discharge with many aspects.