isotherm

noun iso·therm \ ˈī-sə-ˌthərm \

Definition of isotherm

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

See isotherm defined for kids

Recent Examples of isotherm from the Web

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, "How Lightning Can Kill 300 Reindeer With One Strike," 30 Aug. 2016

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'isotherm.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Origin and Etymology of isotherm

French isotherme, adjective

NEW! Time Traveler

First Known Use: 1859

in the meaning defined at sense 1

See Words from the same year

Medical Dictionary

isotherm

noun iso·therm \ ˈī-sə-ˌthərm \

medical Definition of isotherm

: a line on a chart representing changes of volume or pressure under conditions of constant temperature

Learn More about isotherm

Britannica.com: Encyclopedia article about isotherm

Seen and Heard

What made you want to look up isotherm? Please tell us where you read or heard it (including the quote, if possible).

show

WORD OF THE DAY

quail

play

to recoil in dread or terror

BROWSE DICTIONARY

isotheral

isothere

isotherm

isothermal

isothermal curve

Test Your Vocabulary

Name More Food!

Name that Fruit!

How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ

Dictionary Devil

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Words at Play

Ask the Editors

Word Games