From Longman Dictionary of Contemporary Englishisothermi‧so‧therm /ˈaɪsəθɜːm $ -ɜːrm/ noun [countable] technical HEMa line on a weather map joining places where the temperature is the same
Examples from the Corpus
isotherm• An isotherm is a pressure-volume plot at constant temperature.• The boundary between the edge of the southern zone and the tundra is the 2°C July isotherm.• Aleksandrova rather confusingly calls the northern and southern belts arctic tundra and subarctic tundra, separating them by the 6°C July isotherm.• Starting at Cape Sata in the far south, cherry trees burst into flower and a pink isotherm of blossoms sweeps northwards.• The critical temperature of C02 is 304 K. The isotherm at this temperature is called the critical isotherm.• The isotherm for CO2 at 321 K shows that the gas does not liquefy whatever the pressure or volume at this temperature.• The winter isotherm for this might well be above the next critical temperature for water, i.e. 30°C.Origin isotherm (1800-1900) French isotherme, from Greek iso- ( → ISO-) + therme “heat” 