[noun ree-ley; verb ree-ley, ri-ley]
See more 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.
  3. Sports.
    1. relay race.
    2. a length or leg in a relay race.
  4. 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.
  5. 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.
  6. (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.
  3. 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

1375–1425; (v.) late Middle English relaien to unleash fresh hounds in a hunt < Middle French relaier, Old French: to leave behind, release, equivalent to re- re- + laier to leave, dialectal variant of laissier < Latin laxāre (see relax); (noun) late Middle English relai set of fresh hounds < Middle French, derivative of relaier


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


or re·lay

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

Origin of re-lay

First recorded in 1580–90; re- + lay1
Can be confusedre-lay relay Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Related Words for relay

deliver, communicate, send, broadcast, carry, transfer, spread

Examples from the Web for relay

Contemporary Examples of relay

Historical Examples of relay

  • At the end of ten miles or so a relay mount was waiting for each rider.

    When the West Was Young

    Frederick R. Bechdolt

  • A relay snapped, and instantly the ammeter jumped to read 4500 amperes.

    Islands of Space

    John W Campbell

  • Behind him a row of other exhorters sat, a relay ready to leap to his aid.

  • Don Mathers adjusted the screen to relay the Kraden cruiser.

    Medal of Honor

    Dallas McCord Reynolds

  • It was during a relay that Porthos ventured to interrogate Aramis discreetly.

    The Man in the Iron Mask

    Alexandre Dumas, Pere

British Dictionary definitions for relay


noun (ˈriːleɪ)
  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
  3. the act of relaying or process of being relayed
    1. short for relay race
    2. one of the sections of a relay race
  4. an automatic device that controls the setting of a valve, switch, etc, by means of an electric motor, solenoid, or pneumatic mechanism
  5. electronics an electrical device in which a small change in current or voltage controls the switching on or off of circuits or other devices
  6. radio
    1. a combination of a receiver and transmitter designed to receive radio signals and retransmit them, in order to extend their range
    2. (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
  3. to retransmit (a signal) by means of a relay
  4. British to broadcast (a performance) by sending out signals through a transmitting stationthis concert is being relayed from the Albert Hall

Word Origin for 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

Word Origin and History for relay

late 14c., "hounds placed along a line of chase," from Middle French relai "reserve pack of hounds or other animals" (13c.), from Old French relaier "to exchange tired animals for fresh," literally "leave behind," from re- "back" (see re-) + laier "to leave" (see delay (v.)). The etymological sense is "to leave (dogs) behind (in order to take fresh ones)." Of horses, 1650s. Electromagnetic sense first recorded 1860. As a type of foot-race, it is attested from 1898.


c.1400, "to set a pack of (fresh) hounds after a quarry;" also "change horses," from Old French relaiier, from relai (see relay (n.)). Related: Relayed; relaying.



"to lay again," 1590s, from re- + lay (v.). Related: Re-laid; re-laying.

Online Etymology Dictionary, © 2010 Douglas Harper

relay in Science


  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.