# isotherm

> English word · Noun · IPA /ˈaɪ.səʊˌθɜː(ɹ)m/ · frequency rank #98,274

## Definitions
1. A line on a graph or chart, such as a weather map, along which all the points have the same temperature.

## Etymology
From the French isotherme (“of equal temperature”, adjective), itself from Ancient Greek ἴσος (ísos, “equal”) + θέρμη (thérmē, “warmth”). By surface analysis, iso- + -therm.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/isotherm