iso·​therm | \ˈī-sə-ˌthərm \

Definition of isotherm 

1 : a line on a map or chart of the earth's surface connecting points having the same temperature at a given time or the same mean temperature for a given period

2 : a line on a chart representing changes of volume or pressure under conditions of constant temperature

Examples of isotherm in a Sentence

Recent Examples on the Web

Both locations sit at something called a zero degree isotherm, where the average air temperature hovers right around the freezing point of water. Megan Molteni, WIRED, "How Lightning Can Kill 300 Reindeer With One Strike," 30 Aug. 2016

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

First Known Use of isotherm

1859, in the meaning defined at sense 1

History and Etymology for isotherm

French isotherme, adjective

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The first known use of isotherm was in 1859

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iso·​therm | \ˈī-sə-ˌthərm \

Medical Definition of isotherm 

: a line on a chart representing changes of volume or pressure under conditions of constant temperature

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to enclose within walls

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