isotherm

[ahy-suh-thurm]

noun

Meteorology. a line on a weather map or chart connecting points having equal temperature.
Also called isothermal line. Physics. a curve on which every point represents the same temperature.

Origin of isotherm

First recorded in 1855–60; back formation from isothermal

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for isotherm

Historical Examples of isotherm

This is shown by the isotherm for -4.5, which surrounds the point Q, the melting point of the ternary salt.
The Phase Rule and Its Applications
Alexander Findlay
The scale must, however, be laid perpendicularly to the isotherm, as before.
Practical Exercises in Elementary Meteorology
Robert DeCourcy Ward
Isotherm, a compound of two Greek words meaning equal temperature, is the name given in meteorology to such lines as this.
Practical Exercises in Elementary Meteorology
Robert DeCourcy Ward
Draw an isotherm east and west across the map, through your station.
Practical Exercises in Elementary Meteorology
Robert DeCourcy Ward
On a second blank weather map draw an isotherm through your station inclined from northwest to southeast.
Practical Exercises in Elementary Meteorology
Robert DeCourcy Ward

British Dictionary definitions for isotherm

isotherm

noun

a line on a map linking places of equal temperature
physics a curve on a graph that connects points of equal temperature

Also called: isothermal, isothermal line

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for isotherm

1860, from French isotherme (Humboldt, 1817), from Greek iso- (see iso-) + therme "heat" (see thermal).

isotherm in Science

isotherm

[ī′sə-thûrm′]

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.