en·​thal·​py | \ ˈen-ˌthal-pē How to pronounce enthalpy (audio) , en-ˈthal- How to pronounce enthalpy (audio) \

Definition of enthalpy

: the sum of the internal energy of a body or system and the product of its volume multiplied by the pressure

Examples of enthalpy in a Sentence

Recent Examples on the Web The project will test hypersonic reactions inside UCF’s unique hypersonic high-enthalpy reaction, or HyperREACT, facility which was in part created and designed by Rosato. Natalia Jaramillo, orlandosentinel.com, 1 Dec. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'enthalpy.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of enthalpy

1909, in the meaning defined above

History and Etymology for enthalpy

borrowed from Dutch enthalpie, from Greek enthálpein "to impart warmth" (from en- en- entry 2 + thálpein "to warm, heat," probably a syncopated form of the base seen in thalykrós "warm, glowing," of pre-Greek origin) + Dutch -ie -y entry 2

Note: The word was introduced in print by the Irish-born (later South African) mathematician and physicist John Patrick Dalton (1886-1965) in "Researches on the Joule-Kelvin effect, especially at low temperatures. I. Calculations for hydrogen," Koninklijke Akademie van Wetenschappen te Amsterdam, Proceedings of the Section of Sciences, vol. 11, 2nd part (July, 1909), p. 864. This paper was published as a translation of the Dutch original, "Onderzoekingen over het Joule-Kelvin-effect in het bijzonder bij lage temperaturen. I. Berekeningen voor waterstof," presented by the Dutch physicist Heike Kammerlingh Onnes (1853-1926) as a report to the March 27, 1909, meeting of the mathematics and physics division of the Royal Netherlands Academy of Sciences (Verslag van de gewone vergaderingen der Wis- en Natuurkundige Afdeeling, deel 17, 2de gedeelte [May, 1909], pp. 924-34). Dalton, a temporary researcher in Leiden, presumably wrote his paper in English, so that what is presented as an English translation is most likely the original, with the Dutch report being a translation by Onnes and/or the editors of the journal. On the first occurrence of the word enthalpy, Dalton mentions in a footnote that "this name has been suggested by Kamerlingh Onnes to indicate the function (ε + pv) —the 'Heat function' of Gibbs." Onnes himself does not appear to have used the word earlier, at least in publications (see Hendrick C. Van Ness, "H is for Enthalpy," letter to Journal of Chemical Education, vol. 80, no. 5 [May, 2003], p. 486).

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The first known use of enthalpy was in 1909

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Last Updated

13 Dec 2021

Cite this Entry

“Enthalpy.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/enthalpy. Accessed 18 Jan. 2022.

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More Definitions for enthalpy


en·​thal·​py | \ ˈen-ˌthal-pē How to pronounce enthalpy (audio) , en-ˈ How to pronounce enthalpy (audio) \
plural enthalpies

Medical Definition of enthalpy

: the sum of the internal energy of a body and the product of its volume multiplied by the pressure

More from Merriam-Webster on enthalpy

Britannica.com: Encyclopedia article about enthalpy


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