A line drawn on a weather map or chart linking all points of equal or constant temperature.
A line on a map connecting points on the earth's surface having the same mean temperature or the same temperature at a given time.
A line representing changes of volume or pressure at constant temperature.
A line drawn on a weather map connecting points that have the same temperature. Each point can mark one temperature reading or an average of several readings.
Origin of isotherm
- From French isotherme having the same temperature Greek īso- iso- Greek thermē heat –therm
From American Heritage Dictionary of the English Language, 5th Edition
- From the French adjective isotherme (“of equal temperature”), itself from Ancient Greek ἴσος (isos, “equal”) + θέρμη (thermē, “warmth”)