Combustion refers to the chemical reaction that occurs when a substance reacts with oxygen, releasing energy in the form of heat and light. Synonyms for the word combustion include burning, incineration, ignition, and conflagration. Other related words include explosion, flare-up, and blaze. The term combustion is commonly used in the context of engines and fuels, where combustion is necessary to produce energy. Combustion can also refer to the rapid degradation or destruction of something, such as a relationship or a business venture. Regardless of the context in which it is used, the term combustion implies a rapid and often intense process that results in the release of energy.