or i·so·ther·mic

[ahy-suh-thur-muh l]
  1. Meteorology. an isotherm.

Origin of isothermal

1820–30; < French isotherme isothermal (< Greek iso- iso- + thérmē heat) + -al1
Related formsi·so·ther·mal·ly, adverb Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for isothermally


  1. (of a process or change) taking place at constant temperature
  2. of or relating to an isotherm
  1. another word for isotherm
Derived Formsisothermally, adverb
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 isothermally


1826 (adj.); 1852 (n.), from French isotherme (see isotherm) + -al (1).

Online Etymology Dictionary, © 2010 Douglas Harper

isothermally in Medicine


  1. Of, relating to, or indicating equal or constant temperatures.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

isothermally in Science


  1. Relating to or indicating equal or constant temperatures.
  2. Relating to a process, usually changes of pressure and volume, occurring at a constant temperature and following Boyle's Law.
  3. Relating to an isotherm.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.