Relay /(r?-l?")/

imp. & p. p. Relaid; p. pr. & vb. n. Relaying

1. To lay again; to lay a second time; as, to relay a pavement.

1. A supply of anything arranged beforehand for affording relief from time to time, or at successive stages; provision for successive relief.
2. In various forms of telegraphic apparatus, a magnet which receives the circuit current, and is caused by it to bring into into action the power of a local battery for performing the work of making the record; also, a similar device by which the current in one circuit is made to open or close another circuit in which a current is passing. (Elec.)

1. Relating to, or having the characteristics of, an auxiliary apparatus put into action by a feeble force but itself capable of exerting greater force, used to control a comparatively powerful machine or appliance. (Mach.)