gas

American  

[gas] / gæs /

noun

plural

gases, gasses

1. Physics. a substance possessing perfect molecular mobility and the property of indefinite expansion, as opposed to a solid or liquid.

2. any such fluid or mixture of fluids.

3. any such fluid used as an anesthetic, as nitrous oxide.

   Did the dentist give you gas for your extraction?

4. any such combustible fluid used as fuel.

   Light the gas in the oven.

5. Automotive.

   1. gasoline.

   2. Also called gas pedal.  the foot-operated accelerator of an automotive vehicle.

      Take your foot off the gas.

6. flatus.

7. Coal Mining. an explosive mixture of firedamp with air.

8. an aeriform fluid or a mistlike assemblage of fine particles suspended in air, used in warfare to asphyxiate, poison, or stupefy an enemy.

9. Slang.

   1. empty talk.

   2. a person or thing that is very entertaining, pleasing, or successful.

      The party was an absolute gas, and we loved it.

   3. a person or thing that affects one strongly.

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verb (used with object)

gassed, gassing

1. to supply with gas.

2. to overcome, poison, or asphyxiate with gas or fumes.

3. to singe (yarns or fabrics) with a gas flame to remove superfluous fibers.

4. to treat or impregnate with gas.

5. Slang.

   1. to talk nonsense or falsehood to.

   2. to amuse or affect strongly.

      Her weird clothes really gas me.

verb (used without object)

gassed, gassing

1. to give off gas, as a storage battery being charged.

2. Slang.

   1. to indulge in idle, empty talk.

   2. to become drunk (often followed byup ).

verb phrase

1. gas up to fill the gasoline tank of an automobile, truck, or other vehicle.

idioms

1. step on the gas, to increase the speed of one's movement or activity; hurry.

   We'd better step on the gas or we'll be late for the concert.

gas British  

/ ɡæs /

noun

1. a substance in a physical state in which it does not resist change of shape and will expand indefinitely to fill any container. If very high pressure is applied a gas may become liquid or solid, otherwise its density tends towards that of the condensed phase Compare liquid solid

2. any substance that is gaseous at room temperature and atmospheric pressure

3. any gaseous substance that is above its critical temperature and therefore not liquefiable by pressure alone Compare vapour

4. 1. a fossil fuel in the form of a gas, used as a source of domestic and industrial heat See also coal gas natural gas

   2. ( as modifier )

      a gas cooker

      gas fire

5. a gaseous anaesthetic, such as nitrous oxide

6. mining firedamp or the explosive mixture of firedamp and air

7. the usual US, Canadian, and New Zealand word for petrol See also gasoline

8. informal

   1. to increase the speed of a motor vehicle; accelerate

   2. to hurry

9. a toxic or suffocating substance in suspension in air used against an enemy

10. informal idle talk or boasting

11. slang a delightful or successful person or thing

    his latest record is a gas

12. an informal name for flatus

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verb

1. (tr) to provide or fill with gas

2. (tr) to subject to gas fumes, esp so as to asphyxiate or render unconscious

3. (intr) to give off gas, as in the charging of a battery

4. (tr) (in textiles) to singe (fabric) with a flame from a gas burner to remove unwanted fibres

5. informal to talk in an idle or boastful way (to a person)

6. slang (tr) to thrill or delight

gas Scientific  

/ găs /

1. One of four main states of matter, composed of molecules in constant random motion. Unlike a solid, a gas has no fixed shape and will take on the shape of the space available. Unlike a liquid, the intermolecular forces are very small; it has no fixed volume and will expand to fill the space available.

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gas Cultural  

1. In physics, one of the phases of matter. The atoms or molecules in gases are more widely spaced than in solids or liquids and suffer only occasional collisions with one another.

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gas More Idioms  

More idioms and phrases containing gas

• cook with gas
• run out of steam (gas)

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Other Word Forms

• gasless adjective
• nongas noun

Etymology

Origin of gas

First recorded in 1650–60; coined by J. B. van Helmont (1577–1644), Flemish chemist; suggested by Greek cháos “atmosphere”

Explanation

Matter can be found in solid, liquid, or gas form. The air you breathe in and the carbon dioxide you breathe out, are both examples of gas. Gasoline is a kind of a gas that you use as car fuel, and when people say they need gas, usually this is the kind they're talking about. They're probably not talking about the digestive kind of gas that causes you to fart. There are poisons that can be released as gas, and you might hear about riot police somewhere gassing people: spraying them with harmful gas. Gas has no fixed shape and changes density easily.

Example Sentences

Partially because when it comes to budgeting, I actually don’t think the amount of money you allocate toward groceries and gas and entertainment is all that different from your partnered peers.

From MarketWatch • Apr. 29, 2026

At the same time, buyers in Europe and Asia are bidding up prices for crude, fuel and liquefied natural gas from regions far afield of the conflict.

From The Wall Street Journal • Apr. 29, 2026

Groceries and gas have only gotten more expensive.

From Salon • Apr. 29, 2026

One possibility is the Milky Way's central bar, whose gravity may cause gas to accumulate at certain radii.

From Science Daily • Apr. 29, 2026

I didn’t want to face Rae Ellen inside the store, so I waited outside on the sagging bench near the gas pumps.

From "The Seven Wonders of Sassafras Springs" by Betty G. Birney

Related Words

• smoke
• vapor