exothermic reaction exothermic • exothermous · · · Info · Definitions · Characters · · exothermic reaction · · Text Common · · Latin · · Scripts 19 · · Length 7 · · Syllables Definitions · · · (noun) a chemical reaction accompanied by the evolution of heat. Synonyms: exothermic reaction. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 c latin small letter c U+0063 e latin small letter e U+0065 h latin small letter h U+0068 i latin small letter i U+0069 m latin small letter m U+006D n latin small letter n U+006E o latin small letter o U+006F r latin small letter r U+0072 t latin small letter t U+0074 x latin small letter x U+0078