isotherm
noun
iso·therm
ˈī-sə-ˌthərm 
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
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Joining the exodus were a 70-year-old Syrian grandmother with only flip-flops to protect her feet from piercing cold and a six-day-old baby from Afghanistan wrapped in an isotherm bag.
—
David Gauthier-Villars, WSJ, 4 Mar. 2020
The isotherm lines on Humboldt’s map had ups and downs that deviated from lines of latitude.
—Greg Miller, Smithsonian, 16 Oct. 2019
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, 30 Aug. 2016
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David Gauthier-Villars, WSJ, 4 Mar. 2020
The isotherm lines on Humboldt’s map had ups and downs that deviated from lines of latitude.
—Greg Miller, Smithsonian, 16 Oct. 2019
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, 30 Aug. 2016
Cite this Entry
“Isotherm.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/isotherm. Accessed 2 Jul. 2025.
Copy CitationKids Definition
isotherm
noun
iso·therm
ˈī-sə-ˌthərm
: a line on a map connecting points having the same temperature
Medical Definition
isotherm
noun
iso·therm
ˈī-sə-ˌthərm
: a line on a chart representing changes of volume or pressure under conditions of constant temperature
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