Relay

—1l. A device for opening or closing a local circuit under given conditions in the main circuit. 2. In telegraphy, an auxiliary electromagnet which receives the current from the line, and is thereby actuated to open and close the circuit of a local battery, and furnish to the receiver a current of requisite strength. 3. A telephone repeater, in which a microphone is acted upon by the receiver of the first line circuit so as to introduce a local circuit which, in turn, acts inductively on the second line wire.