or ex·o·ther·mal


adjective Chemistry.

noting or pertaining to a chemical change that is accompanied by a liberation of heat (opposed to endothermic).

Nearby words

  1. exosporium,
  2. exostosis,
  3. exostosis cartilaginea,
  4. exoteric,
  5. exoterica,
  6. exotic,
  7. exotic dancer,
  8. exotica,
  9. exoticism,
  10. exoticize

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. 2019

British Dictionary definitions for exothermal




(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 exothermal



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

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for exothermal




Of or relating to a chemical reaction during which heat is released.
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.

Science definitions for exothermal



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.