reducing

from the GNU version of the Collaborative International Dictionary of English.

• a & n. from reduce.
• (Metal.) a furnace for reducing ores.
• a pipe fitting, as a coupling, an elbow, a tee, etc., for connecting a large pipe with a smaller one.
• 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.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb Present participle of reduce.
• adjective chemistry That causes reduction.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any process in which electrons are added to an atom or ion (as by removing oxygen or adding hydrogen); always occurs accompanied by oxidation of the reducing agent
• noun loss of excess weight (as by dieting); becoming slimmer