—n. 1. Physics.a substance possessing perfect molecular mobility and the property of indefinite expansion, as opposed to a solid or liquid.
2. any such fluid or mixture of fluids.
3. any such fluid used as an anesthetic, as nitrous oxide: Did the dentist give you gas for your extraction? 4. any such combustible fluid used as fuel: Light the gas in the oven. 5. Auto. a. gasoline.
b. Also calledgas pedal. the foot-operated accelerator of an automotive vehicle: Take your foot off the gas. 6. flatus.
7. Coal Mining.an explosive mixture of firedamp with air.
8. an aeriform fluid or a mistlike assemblage of fine particles suspended in air, used in warfare to asphyxiate, poison, or stupefy an enemy.
9. Slang. a. empty talk.
b. a person or thing that is very entertaining, pleasing, or successful: The party was an absolute gas, and we loved it. c. a person or thing that affects one strongly.
10. step on the gas,Informal.to increase the speed of one's movement or activity; hurry: We'd better step on the gas or we'll be late for the concert.
—v.t. 1. to supply with gas.
2. to overcome, poison, or asphyxiate with gas or fumes.
3. to singe (yarns or fabrics) with a gas flame to remove superfluous fibers.
4. to treat or impregnate with gas.
5. Slang. a. to talk nonsense or falsehood to.
b. to amuse or affect strongly: Her weird clothes really gas me.
—v.i. 1. to give off gas, as a storage battery being charged.
2. Slang. a. to indulge in idle, empty talk.
b. to become drunk (often fol. by up).
3. gas up,to fill the gasoline tank of an automobile, truck, or other vehicle.