gas
n. C / Un. a substance like air that is not solid or liquid. You use this word for the fuel you use to cook or the fuel you put in a car.
n. a substance in a physical state in which it expands freely to fill any container, having no fixed shape and no fixed volume. Often used as a shorthand for gasoline in North American English or for natural gas used as fuel.
I need to stop and get some gas for the car.
The kitchen uses gas for the stove because it heats up much faster than an electric burner.
Physicists study how the molecules in a gas move rapidly and randomly, colliding with one another and the walls of their container to create pressure.
Uncountable when referring to the state of matter or fuel; countable when referring to specific types or mixtures of gases.
The car is out of the gasThe car is out of gasWhen referring to fuel in a general sense, the noun is uncountable and does not take a definite article.