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early 15c., from Old French combustion (13c.), from Latin combustionem (nominative combustio) "a burning," noun of action from past participle stem of Latin comburere "to burn up, consume," from com-, intensive prefix (see com-), + *burere, faulty separation of amburere "to burn around," actually ambi-urere, from urere "to burn, singe," from PIE root *eus- "to burn" (see ember).
combustion com·bus·tion (kəm-bŭs'chən)
The process of burning.
A chemical change, especially oxidation, accompanied by the production of heat and light.
rapid chemical reaction between substances that is usually accompanied by generation of heat and light in the form of flame. In most cases, oxygen comprises one of the reactants. Other physical phenomena that sometimes occur during combustion reactions are explosion and detonation.