Feedwater

Part of speech: noun

Definitions

1. Water that is pumped into a boiler or steam generator, where it is heated to produce steam for power or industrial processes
2. The liquid supplied to a boiler so that it can be converted into steam for driving turbines or engines
3. Treated water fed into a boiler system to be turned into steam for generating power or running industrial equipment

Etymology: Feedwater is about as transparent as compounds get: it is simply "feed" joined to "water," with no hidden story behind the pairing. In this sense, "feed" is the boiler sense of supplying something continuously to a machine, so the word names the water that is fed into a boiler to replace what has been turned to steam. The meaning is literal and technical, and the compound describes exactly what the water does. The more interesting part is how well the two halves fit together in industrial practice. A steam boiler only works as long as its supply is steady, so the feedwater system, with its pumps and tanks, is as central to the engine as the fire itself. Because the water is later pumped back into the boiler again and again, its purity matters greatly, since impurities build up as scale and corrode metal. That is why the term appears so often in discussions of power plants and steam engines, where water quality is a constant concern.