An aëriform fluid; -- a term used at first by chemists as synonymous with air, but since restricted to fluids supposed to be permanently elastic, as oxygen, hydrogen, etc., in distinction from vapors, as steam, which become liquid on a reduction of temperature. In present usage, since all of the supposed permanent gases have been liquified by cold and pressure, the term has resumed nearly its original signification, and is applied to any substance in the elastic or aëriform state.
- The state of matter distinguished from the solid and liquid states by relatively low density and viscosity, relatively great expansion and contraction with changes in pressure and temperature, the ability to diffuse readily, and the spontaneous tendency to become distributed uniformly throughout any container.
- A substance in the gaseous state.
- A gaseous fuel, such as natural gas.
- The speed control of a gasoline engine. Used with the: Step on the gas.
- A gaseous asphyxiant, irritant, or poison.
- A gaseous anesthetic, such as nitrous oxide.
- Slang Idle or boastful talk.
- Slang Someone or something exceptionally exciting or entertaining: The party was a gas.
- To treat chemically with gas.
- To overcome, disable, or kill with poisonous fumes.
- To give off gas.
- Slang To talk excessively.
- gas up To supply a vehicle with gas or gasoline: gas up a car; gassed up before the trip.