Ground

In electrical engineering (and audio engineering), “ground” or “earth” is the reference point in an electrical circuit from which voltages are measured, a common return path for electric current or a direct physical connection to the earth (via a conductive rod driven into the ground). In wiring for audio, a screen around circuitry or wires connected to the ground shields from electrical/electromagnetic noise. In electricity supply (mains installations), the ground wire provides an alternating route for current to flow back to the ground if there is a fault in the wiring system.