gas 
(găs)
(găs)n. pl. gas·esor gas·ses
1.
a. 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.
b. A substance in the gaseous state.
2. Any of various mixtures of flammable gases used for lighting, heating, or cooking.
3. Gasoline.
4. The speed control of a gasoline engine. Used with the: Step on the gas.
5. A gaseous asphyxiant, irritant, or poison.
6. A gaseous anesthetic, such as nitrous oxide.
7.
a. Flatulence.
b. Flatus.
8. Slang Idle or boastful talk.
9. Slang Someone or something exceptionally exciting or entertaining: The party was a gas.
v. gassed, gas·sing, gas·esor gas·ses
v. tr.
1. To treat chemically with gas.
2. To overcome, disable, or kill with poisonous fumes.
v. intr.
Phrasal Verb: 1. To give off gas.
2. Slang To talk excessively.
gas up
To supply a vehicle with gas or gasoline: gas up a car; gassed up before the trip.
[Dutch, an occult physical principle supposed to be present in all bodies, alteration of Greek khaos, chaos, empty space, coined by Jan Baptista van Helmont (1577-1644), Flemish chemist.]