1. A British term for gasoline, or gas, for motor-driven vehicles: On their holiday in England Jerry and Janice stopped at a fuel station to fill their rented car with petrol.
2. Any of numerous organic compounds, such as benzene and methane, that contain carbon and hydrogen as well as octane, heptane, hexane, etc., which are extracted from petroleum and primarily used as a fuel in internal-combustion engines: Petrol is known to contain such ingredients as corrosion inhibitors and antiknock compounds and lighter hydrocarbons from gasoline that can be used in dirigible balloons.
3. Etymology: "gasoline" from French pétrol (1892); earlier used (1585) in reference to the unrefined substance, from Middle French petrole, "petroleum"; from Old French; from Modern Latin petroleum.