: 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
Example Sentences
Recent Examples on the WebJoining 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