A relay is an electric switch operated by a signal in one circuit to control another circuit.
Relay may also refer to:
Electrical engineering Protective relay, a device designed to trip a circuit breaker when a fault is detected.
Historical Stage station, a place where exhausted horses being used for transport could be exchanged for fresh ones Cursus publicus, a courier service in the Roman Empire Relay league, a chain of message-forwarding stations
Computer networking BITNET Relay, a 1980s online chat system Mail relay, a server used for forwarding e-mail Open mail relay, such a server that can be used by anyone
Other telecommunication Relay (satellite) Broadcast relay station, a transmitter which repeats or transponds the signal of another Microwave radio relay Relay channel, in information theory, a communications probability modeling system Telecommunications Relay Service, a telephone accessibility service for the deaf Repeater, an electronic device that receives and retransmits a signal
Automobiles Citroën Relay, a marketing name for the Fiat Ducato van Saturn Relay, a 2005-2007 minivan
Other uses Relay (shop), a France-based chain of convenience stores Relay (company), a peer-to-peer political texting platform Relay (film), a 2024 thriller film "Relay" (song), 1972, by The Who Relay bid, in contract bridge Relay race, completed in parts by several participants of a team Relay neuron, in anatomy Relay box, a piece of postal infrastructure. Relay (podcast network)
See also Retransmission (disambiguation) Relais