The lack of enduring qualities (used chiefly of plant parts)

• The tendency of a gas to expand or escape

Wikipedia Word definitions in Wikipedia
In chemical thermodynamics , the fugacity of a real gas is an effective partial pressure which replaces the mechanical partial pressure in an accurate computation of the chemical equilibrium constant. It is equal to the pressure of an ideal gas which has ...

WordNet Word definitions in WordNet
n. the tendency of a gas to expand or escape the lack of enduring qualities (used chiefly of plant parts) [syn: fugaciousness ]

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Fugacity \Fu*gac"i*ty\, a. [L fugacitas: cf. F. fugacit['e].] The quality of being fugacious; fugaclousness; volatility; as, fugacity of spirits. --Boyle. Uncertainty; instability. --Johnson.

Wiktionary Word definitions in Wiktionary
n. 1 A measure of the tendency of a fluid to expand or escape 2 (context physics English) A measure of the relative stability of different phases of a substance under the same conditions 3 transience