= gas I fill up the tank with gasoline about once a week. leaded/unleaded gasoline See related entries: Parts of a car Word Origin mid 19th cent.: from gas + -ol + -ine (or -ene).Extra examples Can you smell gasoline? During high school he pumped gasoline to make some money. My car runs on unleaded gasoline. Smaller cars don’t guzzle so much gasoline. They can’t resist pouring gasoline on a raging fire. We ran out of gasoline and had to walk. A fire started in a gasoline station near the harbour. They bought a ten-gallon can of gasoline.