Releasing heat: an exothermic reaction. (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "exothermic" in a sentence
"So when you actually generate the chloroform, that chemical reaction is what ` s called exothermic, so it generates quite a good deal of heat, and that heat can get out of hand."
"This reaction is exothermic, that is, it releases heat, and will occur spontaneously in the presence of a nickel or ruthenium catalyst nickel is cheaper, ruthenium is better."
"This process is exothermic, meaning that it releases heat."