1.NounAn explosion or sudden report made by the near-instantaneous decomposition or combustion of unstable substances. Specifically, combustion that spreads supersonically via shock compression.
"the detonation of gun cotton; a nuclear detonation; carbon detonation"
2.NounAny sudden explosion made by an exothermic process (whether chemical or not) that produces a supersonic shock wave.
"a nuclear detonation; carbon detonation"
3.NounEngine knocking, a type of improper combustion in gasoline piston engines.