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
Words nearby working substance
working order,
working papers,
working party,
working rail,
working storage,
working substance,
working week,
working-capital fund,
working-day,
workingman,
workingperson
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