[ noun ree-ley; verb ree-ley, ri-ley ]
See synonyms for relay on
  1. a series of persons relieving one another or taking turns; shift.

  2. a fresh set of dogs or horses posted in readiness for use in a hunt, on a journey, etc.

  1. Sports.

  2. Machinery. an automatic control device in which the settings of valves, switches, etc., are regulated by a powered element, as a motor, solenoid, or pneumatic mechanism actuated by a smaller, sensitive element.

  3. Electricity. a device, usually consisting of an electromagnet and an armature, by which a change of current or voltage in one circuit is used to make or break a connection in another circuit or to affect the operation of other devices in the same or another circuit.

  4. (initial capital letter)U.S. Aerospace. one of an early series of experimental low-altitude, active communications satellites.

verb (used with object),re·layed, re·lay·ing.
  1. to carry forward by or as if by relays: to relay a message.

  2. to provide with or replace by fresh relays.

  1. Electricity. to retransmit (a signal, message, etc.) by or as if by means of a telegraphic relay.

verb (used without object),re·layed, re·lay·ing.
  1. Electricity. to retransmit a signal or message electronically.

Origin of relay

First recorded in 1375–1425; (for the verb) late Middle English relaien “to unleash fresh hounds in a hunt,” from Middle French relaier, Old French: “to leave behind, release,” from re- re- + laier “to leave” (dialectal variant of laissier, from Latin laxāre; see relax); (for the noun) late Middle English relai “set of fresh hounds,” from Middle French, derivative of relaier

Other definitions for relay (2 of 3)

[ ree-ley ]

verb (used with object),re·laid, re·lay·ing.

Other definitions for re-lay (3 of 3)


or re·lay

[ ree-ley ]

verb (used with object),re-laid, re-lay·ing.
  1. to lay again.

Origin of re-lay

First recorded in 1580–90; re- + lay1

Words that may be confused with re-lay Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use relay in a sentence

British Dictionary definitions for relay


  1. a person or team of people relieving others, as on a shift

  2. a fresh team of horses, dogs, etc, posted at intervals along a route to relieve others

  1. the act of relaying or process of being relayed

    • short for relay race

    • one of the sections of a relay race

  2. an automatic device that controls the setting of a valve, switch, etc, by means of an electric motor, solenoid, or pneumatic mechanism

  3. electronics an electrical device in which a small change in current or voltage controls the switching on or off of circuits or other devices

  4. radio

    • a combination of a receiver and transmitter designed to receive radio signals and retransmit them, in order to extend their range

    • (as modifier): a relay station

verb(rɪˈleɪ) (tr)
  1. to carry or spread (something, such as news or information) by relays

  2. to supply or replace with relays

  1. to retransmit (a signal) by means of a relay

  2. British to broadcast (a performance) by sending out signals through a transmitting station: this concert is being relayed from the Albert Hall

Origin of relay

C15 relaien, from Old French relaier to leave behind, from re- + laier to leave, ultimately from Latin laxāre to loosen; see relax

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for relay


[ ]

  1. An electrical switch that is operated by an electromagnet, such as a solenoid. When a small current passes through the electromagnet's coiled wire, it produces a magnetic field that attracts a movable iron bar, causing it to pivot and open or close the switch.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.