to fill up one's gasoline tank with gasoline. I have to stop at the next service station and gas up.The next time you gas up, try some of the gasoline with alcohol in it.
Supply a vehicle with gasoline, as in I want to be sure to gas up before we go. James M. Cain used this term in The Postman Always Rings Twice (1934): "I went to gas up a car." [Colloquial; c. 1930 Also see tank up.
1. To supply gasoline or fuel to a vehicle: The tank was almost empty, so we stopped at a service station and gassed up.
2. To supply some vehicle or machine with gasoline or fuel: We gassed up the car before the road trip. After fixing the lawn mower, I gassed it up and tried to start it.