noun \ˈgas\

: a substance (such as oxygen or hydrogen) that is like air and has no fixed shape

: a gas or mixture of gases that is burned as a fuel

: gas in your stomach and intestines that causes pain or discomfort

plural gas·es also gas·ses

Full Definition of GAS

:  a fluid (as air) that has neither independent shape nor volume but tends to expand indefinitely
a :  a combustible gas or gaseous mixture for fuel or lighting; especially :  natural gas
b :  a gaseous product of digestion; also :  discomfort from this
c :  a gas or gaseous mixture used to produce anesthesia
d :  a substance that can be used to produce a poisonous, asphyxiating, or irritant atmosphere
:  empty talk :  bombast
:  gasoline; also :  the accelerator pedal of an automotive vehicle
:  driving force :  energy <I was young, and full of gas — H. L. Mencken> <ran out of gas in the seventh inning>
slang :  something that gives pleasure :  delight <the party was a gas>

Examples of GAS

  1. Carbon monoxide is a poisonous gas.
  2. We heat our house with gas.
  3. Do you have a gas stove or an electric one?
  4. The car gets good gas mileage.
  5. The car almost ran out of gas.
  6. He was driving with one foot on the gas and one foot on the brake.

Origin of GAS

New Latin, alteration of Latin chaos space, chaos
First Known Use: 1779

Other Chemical Engineering Terms

alkali, cation, decant, hygroscopic, isotope, oxidize, slurry, solute, viscous



: to poison or kill (someone) with gas

: to put gasoline in (a car, truck, etc.)


Full Definition of GAS

intransitive verb
:  to talk idly or garrulously
:  to give off gas
:  to fill the tank (as of an automobile) with gasoline —usually used with up
transitive verb
:  to supply with gas or especially gasoline <gas up the car>
a :  to treat chemically with gas
b :  to poison or otherwise affect adversely with gas
slang :  to please greatly

Examples of GAS

  1. soldiers gassed on the battlefield
  2. We stopped to gas the car.

First Known Use of GAS



noun    (Concise Encyclopedia)

One of the three fundamental states of matter, in which matter has no definite shape, is very fluid, and has a density about 0.1% that of liquids. Gas is very compressible but tends to expand indefinitely, and it fills any container. A small change in temperature or pressure produces a substantial change in its volume; these relationships are expressed as equations in the gas laws. The kinetic theory of gases, developed in the 19th century, describes gases as assemblages of tiny particles (atoms or molecules) in constant motion and contributed much to an understanding of their behaviour. The term gas can also mean gasoline, natural gas, or the anesthetic nitrous oxide. See also solid.


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