WElectric arc
WArc converter
WArc welding
WArcing horns
WCascaded Arc Plasma Source
WCounterpoise (ground system)
WElectric arc furnace
WElectrical discharge machining
WHigh-Enthalpy Arc Heated Facility
WLightning
WLightning rod
WMercury-arc valve
WPower flash
WSpark gap
WSpark plug
WSpark-gap transmitter