Power symbol

Power On (IEC 60417-5007) and Power Off (IEC 60417-5008) symbols are used to indicate positions of the rocker switch
Power button marked with Standby symbol (IEC 60417-5009) turns the device on or off without fully disconnecting power supply

A power symbol is a symbol indicating that a control activates or deactivates a particular device. Such a control may be a rocker switch, a toggle switch, a push-button, a virtual switch on a display screen, or some other user interface. The internationally standardized symbols are intended to communicate their function in a language-independent manner.