Encyclopedia
Detonation
Detonation (knock): abnormal combustion, often producing an audible sound caused by spontaneous ignition of the fuel-air mixture
Source: "GOST R 52947-2008 (EN ISO 5164:2005). Petroleum products. Determination of detonation characteristics of motor fuels. Research method"
(approved by the order of Rosstandart dated 12 August 2008 No. 169-st)