grand

The reference potential at the ground level. This potential is typically considered to be zero and is used to express the potentials at various points in an electrical circuit. In electrical and electronic devices, it refers to the terminal used for grounding (taking an earth connection). Grounding is important to discharge abnormal voltages to the earth, such as when the equipment becomes charged due to external surges, in order to prevent failure and electric shock. The ground may also be used as a return path for signal lines.