or ex·o·ther·mal


Origin of exothermic

First recorded in 1880–85; exo- + thermic
Related formsex·o·ther·mi·cal·ly, ex·o·ther·mal·ly, adverbex·o·ther·mic·i·ty [ek-soh-ther-mis-i-tee] /ˌɛk soʊ θərˈmɪs ɪ ti/, noun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for exothermicity



  1. (of a chemical reaction or compound) occurring or formed with the evolution of heatCompare endothermic, exoergic
Derived Formsexothermically or exothermally, 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 exothermicity



1879, from French exothermique (1879), from exo- + thermique, ultimately from Greek therme "heat" (see thermal).

Online Etymology Dictionary, © 2010 Douglas Harper

exothermicity in Medicine


  1. Of or relating to a chemical reaction during which heat is released.
  2. Of or relating to the external warmth of the body.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

exothermicity in Science


  1. Relating to a chemical reaction that releases heat. Compare endothermic.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.