<p><strong>Noun</strong></p><ul><li>a series of persons relieving one another or taking turns; shift</li><li>a fresh set of dogs or horses posted in readiness for use in a hunt, on a journey, etc.</li><li>Sports: relay race</li><li>a length or leg in a relay race</li><li>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</li><li>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</li><li>(initial capital letter) U.S. Aerospace: one of an early series of experimental low-altitude, active communications satellites</li></ul><p><strong>Verb (used with object)</strong></p><ul><li>to carry forward by or as if by relays: to relay a message</li><li>to provide with or replace by fresh relays</li></ul><p><strong>Verb (used without object)</strong></p><ul><li>Electricity: to retransmit a signal or message electronically</li></ul>