gas

UK: /ˈgæs/ US: /gæs/ ,(gas)

Inflections of 'gas' (n): npl: gases

Inflections of 'gas' (v): (⇒ conjugate)

gasses

v 3rd person singular

gassing

v pres p

gassed

v past

gassed

v past p

WordReference Random House Learner's Dictionary of American English © 2025

gas /gæs/   n., pl. gas•es, v., gassed, gas•sing. 
n. 

1. Physics a fluid substance with the ability to expand without limit, as opposed to a solid or a liquid:
   [uncountable] huge clouds of gas in outer space.
   [countable] Some gases are lighter than air.
2. Physics, Chemistry any such fluid or mixture of fluids, used as a fuel, anesthetic, choking agent, etc.: [uncountable]:
   The house is heated with natural gas.
   [countable] nerve gases.
3. [uncountable]
   • gasoline:
     gas for a car.
   • [usually: the + ~] the foot-operated accelerator of an automotive vehicle:
     put her foot on the gas.
4. Physiology [uncountable] intestinal gas produced by bacterial action on waste matter in the intestines.
5. [Slang.]
   • [uncountable] empty talk.
   • [countable* usually singular] a person or thing that is very pleasing:
     This party is a gas.

v. 

6. to overcome, poison, or asphyxiate with gas or fumes:
   [~ + object] Entire villages were gassed in the war.
7. • [no object] [Slang.] to indulge in idle talk.
8. Automotive gas up, to fill the gasoline tank of a vehicle: [no object]
   We last gassed up in San Diego.
   [~ + up + object]
   We gassed up the car.
   [~ + object + up]
   We gassed the car up an hour ago.

Idioms

9. Idioms, Informal Terms step on the gas, [Informal.] to increase one's speed:
   You'll have to step on the gas to finish the book in time.

WordReference Random House Unabridged Dictionary of American English © 2025

gas  (gas), n., pl. gas•es, v., gassed, gas•sing. 
n. 

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. [Auto.]
   • gasoline.
   • 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.]
   • empty talk.
   • a person or thing that is very entertaining, pleasing, or successful:
     The party was an absolute gas, and we loved it.
   • a person or thing that affects one strongly.
10. step on the gas, [Informal.] 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.

v.t. 

11. to supply with gas.
12. to overcome, poison, or asphyxiate with gas or fumes.
13. to singe (yarns or fabrics) with a gas flame to remove superfluous fibers.
14. to treat or impregnate with gas.
15. [Slang.]
    • to talk nonsense or falsehood to.
    • to amuse or affect strongly:
      Her weird clothes really gas me.

v.i. 

16. to give off gas, as a storage battery being charged.
17. [Slang.]
    • to indulge in idle, empty talk.
    • to become drunk (often fol. by up).
18. gas up, to fill the gasoline tank of an automobile, truck, or other vehicle.

• 1650–60; coined by J. B. van Helmont (1577–1644), Flemish chemist; suggested by Greek cháos atmosphere

gas′less, adj. 

Collins Concise English Dictionary © HarperCollins Publishers::

gas / ɡæs/ noun (gases, gasses)

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 liquid1, solid1
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 vapour2
4. a fossil fuel in the form of a gas, used as a source of domestic and industrial heat
   See also coal gas, natural gas
5. (as modifier): a gas cooker, gas fire
6. a gaseous anaesthetic, such as nitrous oxide
7. firedamp or the explosive mixture of firedamp and air
8. the usual US, Canadian, and New Zealand word for petrol
   See also gasoline
9. step on the gas ⇒ to increase the speed of a motor vehicle; accelerate
10. to hurry
11. a toxic or suffocating substance in suspension in air used against an enemy
12. idle talk or boasting
13. a delightful or successful person or thing: his latest record is a gas
14. 
    an informal name for flatus

verb (gases, gasses, gassing, gassed)

1. (transitive) to provide or fill with gas
2. (transitive) to subject to gas fumes, esp so as to asphyxiate or render unconscious
3. (intransitive) to give off gas, as in the charging of a battery
4. (transitive) (in textiles) to singe (fabric) with a flame from a gas burner to remove unwanted fibres
5. (intransitive) followed by to: to talk in an idle or boastful way (to a person)
6. (transitive) to thrill or delight

Etymology: 17th Century (coined by J. B. van Helmont (1577–1644), Flemish chemist): modification of Greek khaos atmosphere

ˈgasless adjective