[ gas ]
See synonyms for: gasgasesgassedgassing on

noun,plural gas·es or gas·ses.
  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.

  1. any such fluid used as an anesthetic, as nitrous oxide: Did the dentist give you gas for your extraction?

  2. any such combustible fluid used as fuel: Light the gas in the oven.

  3. Automotive.

    • Also called gas pedal . the foot-operated accelerator of an automotive vehicle: Take your foot off the gas.

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

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

  6. 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.

verb (used with object),gassed, gas·sing.
  1. to supply with gas.

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

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

  2. to treat or impregnate with gas.

  3. Slang.

    • to talk nonsense or falsehood to.

    • to amuse or affect strongly: Her weird clothes really gas me.

verb (used without object),gassed, gas·sing.
  1. to give off gas, as a storage battery being charged.

  2. Slang.

    • to indulge in idle, empty talk.

    • to become drunk (often followed by up).

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

Idioms about gas

  1. 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.

Origin of gas

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

Other words from gas

  • gasless, adjective
  • non·gas, noun, plural non·gas·es.

Words that may be confused with gas Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use gas in a sentence

British Dictionary definitions for gas


/ (ɡæs) /

nounplural gases or 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 liquid (def. 1), solid (def. 1)

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

  1. any gaseous substance that is above its critical temperature and therefore not liquefiable by pressure alone: Compare vapour (def. 2)

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

    • (as modifier): a gas cooker; gas fire

  2. a gaseous anaesthetic, such as nitrous oxide

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

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

  5. step on the gas informal

    • to increase the speed of a motor vehicle; accelerate

    • to hurry

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

  7. informal idle talk or boasting

  8. slang a delightful or successful person or thing: his latest record is a gas

  9. US an informal name for flatus

verbgases, gasses, gassing or gassed
  1. (tr) to provide or fill with gas

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

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

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

  3. (intr foll by to) informal to talk in an idle or boastful way (to a person)

  4. (tr) slang, mainly US and Canadian to thrill or delight

Origin of gas

C17 (coined by J. B. van Helmont (1577–1644), Flemish chemist): modification of Greek khaos atmosphere

Derived forms of gas

  • gasless, adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for gas


[ 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.

Other words from gas

  • gaseous adjective (găsē-əs, găshəs)

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for gas


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.

The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Other Idioms and Phrases with gas


In addition to the idiom beginning with gas

  • gas up

also see:

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

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.