relay1

noun

• 1a group of people or animals engaged in a task or activity for a period of time and then replaced by a similar group:the wagons were pulled by relays of horses gangs of workers were sent in relays
• a race between teams of runners, each team member in turn covering part of the total distance: [as modifier]:a 550-metre relay race

• 2an electrical device, typically incorporating an electromagnet, which is activated by a current or signal in one circuit to open or close another circuit.

• 3a device to receive, reinforce, and retransmit a radio or television signal: [as modifier]:TV transmitters and relay stations
• a signal or broadcast transmitted by a relay:a relay of a performance live from the concert hall

verb

• receive and pass on (information or a message):she intended to relay everything she had learned
• broadcast (something) by passing signals received from elsewhere through a transmitting station:the speech was relayed live from the palace