/ Dictionary / Index F free expansion: Meaning and Definition of Find definitions for: free' expan'sion Pronunciation: [key] — Thermodynamics. Thermodynamics. the expansion of a gas into an evacuated space without the transfer of heat or the performance of work. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. free enterpriser free fall Related Content Daily Word Quiz: tactful Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language