gas

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun 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.
• noun A substance in the gaseous state.
• noun A gaseous fuel, such as natural gas.
• noun Gasoline.
• noun The speed control of a gasoline engine. Used with the:
• noun A gaseous asphyxiant, irritant, or poison.
• noun A gaseous anesthetic, such as nitrous oxide.
• noun Flatulence.
• noun Flatus.
• noun Slang Idle or boastful talk.
• noun Slang Someone or something exceptionally exciting or entertaining.
• intransitive verb To treat chemically with gas.
• intransitive verb To overcome, disable, or kill with poisonous fumes.
• intransitive verb To give off gas.
• intransitive verb Slang To talk excessively.

from The Century Dictionary.

• noun Specifically, nitrous-oxid gas when used to produce anæsthesia, most commonly by dentists.
• To remove loose filaments from (net, lace, etc.) by passing the material between rollers and exposing it to the action of a large number of minute jets of gas.
• To talk nonsense or falsehood to; impose upon by wheedling, frothy, or empty speech.
• To indulge in “gas” or empty talk; talk nonsense.
• To treat with a gas or expose to the action of a gas, as is done with slaked lime in the manufacture of bleaching-powder.
• To overcome or poison by means of the inhalation of gas.
• noun A substance possessing perfect molecular mobility and the property of indefinite expansion.
• noun Specifically In coal-mining, any explosive mixture of fire-damp with common air.
• noun In popular language, a compound of various gases, used for illuminating and heating purposes.
• noun A gas-light: as, the gas is dim; turn down the gas.
• noun Empty or idle talk; frothy speech; rant.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb (Textiles) To singe, as in a gas flame, so as to remove loose fibers.
• transitive verb To impregnate with gas.
• transitive verb to expose to a poisonous or noxious gas.
• noun 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.
• noun A complex mixture of gases, of which the most important constituents are marsh gas, olefiant gas, and hydrogen, artificially produced by the destructive distillation of gas coal, or sometimes of peat, wood, oil, resin, etc. It gives a brilliant light when burned, and is the common gas used for illuminating purposes.
• noun Laughing gas.
• noun Any irrespirable aëriform fluid.
• noun same as gasoline; -- a shortened form. Also, the accelerator pedal of a motor vehicle; used in the term “ step on the gas”.
• noun the accelerator pedal of a motor vehicle; used in the term “ step on the gas”.
• noun Same as natural gas.
• noun slang an exceptionally enjoyable event; a good time.
• noun (Chem.) a kind of gas made by forcing air through some volatile hydrocarbon, as the lighter petroleums. The air is so saturated with combustible vapor as to be a convenient illuminating and heating agent.
• noun (Elec.) a form of voltaic battery, in which gases, especially hydrogen and oxygen, are the active agents.
• noun etc. See under Carbon, Coke, etc.
• noun a bituminous or hydrogenous coal yielding a high percentage of volatile matters, and therefore available for the manufacture of illuminating gas.
• noun an engine in which the motion of the piston is produced by the combustion or sudden production or expansion of gas; -- especially, an engine in which an explosive mixture of gas and air is forced into the working cylinder and ignited there by a gas flame or an electric spark.
• noun one who lays pipes and puts up fixtures for gas.
• noun The appliances needed for the introduction of gas into a building, as meters, pipes, burners, etc.
• noun a device for conveying illuminating or combustible gas from the pipe to the gas-burner, consisting of an appendage of cast, wrought, or drawn metal, with tubes upon which the burners, keys, etc., are adjusted.