Webster’s Revised Unabridged Dictionary · 1913
Regenerator
Re·gen′er·a′tor (-?′t?r), n. 1. One who, or that which, regenerates.
2. (Mech.) A device used in connection with hot-air engines, gas-burning furnaces, etc., in which the incoming air or gas is heated by being brought into contact with masses of iron, brick, etc., which have been previously heated by the outgoing, or escaping, hot air or gas.