learn word relay

Relay refers to the act of passing something along from one person or place to another, or a device that receives a signal and then transmits it to another device or system. It can also refer to a race where each team member runs a portion of the distance before passing the baton to the next runner. In electrical engineering, a relay is an electromechanical device that controls the flow of electricity in a circuit by opening or closing contacts in response to an electrical signal.