Definition of gas in English:

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Pronunciation: /ɡas/

noun (plural gases or gasses)

1An airlike fluid substance which expands freely to fill any space available, irrespective of its quantity: hot balls of gas that become stars poisonous gases
More example sentences
  • The spherical wavefront of expanding gasses and space debris burst past the Aspiration, rocking the vehicle even through the shielding.
  • He looked over his shoulder at the source of the transmission, only to see a rapidly expanding ball of gasses and wreckage.
  • I combined all the ingredients and I tied off the bag leaving plenty of room for the gasses to expand into.
1.1 Physics A gaseous substance that cannot be liquefied by the application of pressure alone. Compare with vapor.
Example sentences
  • Nitrogen dioxide is a brown gas, transformed from nitric oxide contained in emissions.
  • The resulting ester was saponified under basic conditions to the free acid, converted to the acyl chloride with thionyl chloride, and then to the amide with anhydrous ammonia gas.
  • The simplest sources are hydrogen-rich compounds like hydrogen gas, hydrogen sulfide gas and hydrocarbons.
1.2A flammable gas used as a fuel.
Example sentences
  • It can be used as a fuel in power stations to generate electricity or heat as an environmental alternative to burning fossil fuels such as gas, coal and oil.
  • So in the House today, the Greens are advocating, for some reason, the burning of fossil fuels - gas in Auckland and diesel along with wind generation.
  • We can go on to by-products of petroleum such as plastics and with gas as fuel we can do aluminium products with bauxite from Guyana and Jamaica.
1.3A gaseous anesthetic such as nitrous oxide, used in dentistry.
Example sentences
  • Two other reports exist of nitrous oxide anaesthesia being used in patients with intraocular gas in a closed eye.
  • The condor was put under anaesthetic gas for the 20 minute procedure - carried out by zoo vet Brash in Flamingo Land's own clinic a fortnight ago.
  • He compared being so short of hand towels to running out of anaesthetic gas during an operation.
1.4Gas or vapor used as a poisonous agent to kill or disable an enemy in warfare.
Example sentences
  • He made a specialty of chemical and gas warfare and minefields and his war caused a million deaths.
  • Videos from his collection, showing dogs being killed by poisonous gas or a nerve agent, were recently aired on CNN.
  • This year is the 90th anniversary of the invention of modern gas warfare.
1.5North American Gas generated in the alimentary canal; flatulence.
Example sentences
  • This slows down your digestion and can cause gas to build up.
  • For general bloating and gas, over-the-counter products containing simethicone can help.
  • This almost involuntary practice relieves the symptom but it also produces gas and bloating.
1.6 Mining An explosive mixture of firedamp with air.
Example sentences
  • To clear mines of gas - be it explosive or poisonous - a crude system of ventilation was used.
  • Late in the afternoon, during the shift change, an explosion of methane gas, "firedamp," blasted deep in the underground workings.
2North American informal short for gasoline.
Example sentences
  • But we do know she encountered them in her attempt to stop and get gas.
  • The Turkish move to stop buying gas altogether paid off and Iran finally agreed to decrease the prices.
  • Sometimes Bud stops to get gas, and this always feels like a momentous occasion.
2.1Used in reference to power or the accelerator of an automobile: I ordered my friend to step on the gas
More example sentences
  • He stepped on the gas and the rear end of his car first swerved gently to the right, and then to the left.
  • As soon as she was out of the car, Ray stepped on the gas and shot forward, trying to run over my grandmother.
  • The victim reported that she placed her vehicle in reverse and ducked down as she stepped on the gas swerving back and forth out of the immediate intersection.
3 (a gas) informal A person or thing that is entertaining or amusing: the party would be a gas
More example sentences
  • We both thought it a bit crazy at the time, and we also thought it would be a gas.
  • Since then, it's been a rather gentle decline, although many in the UK during the 80s and 90s still thought I was a gas.

verb (gases, gassed, gassing)

[with object]
1Kill or harm by exposure to poisonous gas.
Example sentences
  • But it's only at the end of the film that we learn what appears to have really happened: it is he himself who killed his mother, gassing her whilst apparently suffering from a delusion that she is another person.
  • Six death camps were built in occupied Poland to systematically kill people who were gassed and their bodies burned in crematoria.
  • How would he feel if his father had been gassed, shot or hung in Auschwitz or Dachau, instead of his luckier fate, enjoying a good, long life hurling insults at others?
1.1 [no object] (Of a storage battery or dry cell) give off gas.
Example sentences
  • It is however possible to compress the cell packs subsequent to their formation and prior to inserting them into their final container to expel at least a proportion of their electrolyte which will reduce the amount of electrolyte which needs to be gassed off in the finished cells.
2North American informal Fill the tank of (an engine or motor vehicle) with gasoline: after gassing up the car, he went into the restaurant
More example sentences
  • The left tank was for gassing up the lawnmower, cars, and pickups and the right tank was for fueling the grain truck, the haystack movers, and anything John Deere green.
  • They can gas my car and change four tires in less then fourteen seconds during a pit stop.
  • Tess went into the convenience store to pay as Michael gassed the car.
3 [no object] informal Talk, especially excessively, idly, or boastfully: I thought you’d never stop gassing
More example sentences
  • Elsewhere, Ofcom's Communications Market 2004 report found that people are spending loads more time online, oodles more time gassing on their mobile phones but only a smidgen more watching TV.
  • And LA Weekly opined that ‘Lopez and Affleck try not to smile at each other while gassing on and on until you're praying, dear God, please make them shut up and do it so we can all go home in peace’.
  • First, the idea that the acme of being civilised is lying around your dining table gassing about culture and politics in a nice city, while the slaves do the washing up.


run out of gas

North American informal Run out of energy; lose momentum.
Example sentences
  • He, who tied a record with 30 sets spanning 20 hours in seven matches last year, is trying to conserve energy this time after running out of gas in the 2004 final against Roger.
  • The pop craze over the Kabbalah Centre may have passed and despite the group's energy drink, it may be running out of gas.
  • Now that the yield curve has ‘lost its curve’, this profit engine has run out of gas.


Mid 17th century: invented by J. B. van Helmont (1577–1644), Belgian chemist, to denote an occult principle that he believed to exist in all matter; suggested by Greek khaos 'chaos', with Dutch g representing Greek kh.

  • Gas is an invented word, coined in the 17th century by the Belgian chemist and physician Joannes Baptista van Helmont (1577–1644), who was the first scientist to realize that there are gases other than air, and who discovered carbon dioxide. Van Helmont based the word on Greek khaos, chaos. It did not really catch on until the 19th century, with earlier scientists like Robert Boyle preferring to think of gases as different types of air. Gas for lighting or heating purposes dates from the late 18th century. The first experiments using coal-gas for lighting are said to have been made by the rector of Crofton, Dr Clayton, in about 1688; gas-lighting in its practical application was due to William Murdock (1754–1839).

Words that rhyme with gas

alas, Alsace, amass, Bass, chasse, crass, crevasse, en masse, Hamas, lass, mass, morass, sass, tarantass, tass, wrasse

For editors and proofreaders

Syllabification: gas

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