exothermic

/ˈɛksəˌθʌrmɪk/

In chemistry, something that's exothermic has to do with the release of heat. Burning a candle is an exothermic process, since heat is given off.

The scientific adjective exothermic is good for describing reactions that involve releasing energy, usually in the form of heat. Exothermic processes vary from something as simple as striking a match on a rough surface to a more extreme and violent example — an explosion. Part of what defines an exothermic reaction is that more energy is released than was required to start it. The word's Greek roots are exo, "outside," and therme, "heat."

Definitions of exothermic

1. adjective

   (of a chemical reaction or compound) occurring or formed with the liberation of heat
   synonyms: exothermal, heat-releasing

   energy-releasing, exoergic

   (of a nuclear reaction) occurring with evolution or releasing of energy

   antonyms:

   endothermic

   (of a chemical reaction or compound) occurring or formed with absorption of heat

   endoergic, energy-absorbing

   (of a nuclear reaction) occurring with absorption of energy

   decalescent

   absorbing heat without increase in temperature when heated beyond a certain point