From Reduce.

<chemistry> Reducing furnace, a furnace for reducing ores. Reducing pipe fitting, a pipe fitting, as a coupling, an elbow, a tee, etc, for connecting a large pipe with a smaller one. Reducing valve, a device for automatically maintaining a diminished pressure of steam, air, gas, etc, in a pipe, or other receiver, which is fed from a boiler or pipe in which the pressure is higher than is desired in the receiver.

(01 Mar 1998)