working substance

noun

a substance, usually a fluid, that undergoes changes in pressure, temperature, volume, or form as part of a process for accomplishing work.

Origin of working substance

First recorded in 1895–1900

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for working substance

working substance

working fluid

noun

the fluid, esp water, steam, or compressed air, that operates an engine, refrigerator, etc

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012