An afterburner is a piece of equipment on some jet engines, mostly on fast military planes. It sends extra fuel into the hot gas that is already leaving the engine and burns it there. That gives the plane a sudden extra push of power. It also uses a huge amount of fuel, makes a very loud noise, and often shows a flame at the back. Pilots turn it on to take off in a short space, to climb fast, or to fly very fast. Ordinary passenger planes almost never have one. Though actually, the name sounds like “a burner you add later”, but it is a special part of a jet, not something you bolt onto a car. A car turbo is a different machine: it uses exhaust to spin a fan. An afterburner is extra fire in the jet stream.