fugacity

noun

fu·​gac·​i·​ty fyü-ˈga-sə-tē How to pronounce fugacity (audio)
: the vapor pressure of a vapor assumed to be an ideal gas obtained by correcting the determined vapor pressure and useful as a measure of the escaping tendency of a substance from a heterogeneous system

Examples of fugacity in a Sentence

Recent Examples on the Web
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This difference indicates a notable loss of water by degassing in the form of H2 before the crystallization of apatite under a reduced oxygen fugacity environment24,25. Keith Cooper, Space.com, 16 July 2025

Word History

Etymology

fugacious

First Known Use

1902, in the meaning defined above

Time Traveler
The first known use of fugacity was in 1902

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Cite this Entry

“Fugacity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fugacity. Accessed 30 Jul. 2025.

Medical Definition

fugacity

noun
fu·​gac·​i·​ty fyü-ˈgas-ət-ē How to pronounce fugacity (audio)
plural fugacities
: the vapor pressure of a vapor assumed to be an ideal gas obtained by correcting the determined vapor pressure and useful as a measure of the escaping tendency of a substance from a heterogeneous system

More from Merriam-Webster on fugacity

Last Updated: - Updated example sentences
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