gas

n. (pl. -es) 1 any airlike substance (i.e. Not solid or liquid) moving freely to fill any space available. 2 such a substance (esp. Found naturally or extracted from coal) used as fuel (also attrib.: gas cooker; gas industry). 3 nitrous oxide or other gas as an anaesthetic. 4 poisonous gas used in war. 5 us colloq. Petrol, gasoline. 6 slang idle talk; boasting. 7 slang enjoyable or amusing thing or person. v. (gases, gassed, gassing) 1 expose to gas, esp. To kill. 2 colloq. Talk idly or boastfully.

n. An aeriform 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 aeriform state.