detonation

Short definition from Wiktionary

Noun

1. 1
   An explosion or sudden report made by the near-instantaneous decomposition or combustion of unstable substances. Specifically, combustion that spreads supersonically via shock compression.
2. 2
   An explosion or sudden report made by the near-instantaneous decomposition or combustion of unstable substances. Specifically, combustion that spreads supersonically via shock compression: Any sudden explosion made by an exothermic process (whether chemical or not) that produces a supersonic shock wave.
3. 3
   Engine knocking, a type of improper combustion in gasoline piston engines.