A jump start, also called a boost, is a method of starting an automobile or other vehicle powered by an internal combustion engine when the vehicle's battery has been discharged. A second battery (often in another vehicle) is temporarily connected to provide starting power to the disabled vehicle. Once the disabled vehicle's engine is running, its alternator or generator should recharge the dead battery, so the second battery can be disconnected.

Unter Starthilfe versteht man das Starten eines Verbrennungsmotors bei Versagen der eigenen Starterbatterie.