Definitions
from The American Heritage® Dictionary of the English Language, 5th Edition.
- noun A substance, such as a fluid, used to effect a thermodynamic or other change in a system.
Etymologies
Sorry, no etymologies found.
Support

Help support Wordnik (and make this page ad-free) by adopting the word working substance.
Examples
Sorry, no example sentences found.
Comments
Log in or sign up to get involved in the conversation. It's quick and easy.