gas

Concise Oxford English Dictionary © 2008 Oxford University Press:
gas/ɡas/

▶noun (pl. gases or chiefly US gasses)

• 1 an air-like fluid substance which expands freely to fill any space available, irrespective of its quantity.

  ■ Physics a substance of this type that cannot be liquefied by pressure alone.

  Compare with vapour.

  ■ a flammable gas used as a fuel.

  ■ Mining an explosive mixture of firedamp (methane) with air.

• 2 a gaseous anaesthetic such as nitrous oxide, used in dentistry.

• 3 N. Amer. flatulence.

• 4 N. Amer. informal gasoline; petrol.

• 5 (a gas) informal an entertaining or amusing person or thing.

▶verb (gases, gassing, gassed)

• 1 kill or harm by exposure to gas.

  ■ (of a storage battery or dry cell) give off gas.

• 2 informal talk idly; chatter.

• 3 N. Amer. informal fill the tank of (a motor vehicle) with petrol.

– derivatives
gasification noun,
gasify verb (gasifies, gasifying, gasified),
gasser noun.

– origin C17: invented by the Belgian chemist J. B. van Helmont to denote an occult principle which he believed to exist in all matter; suggested by Gk khaos ‘chaos’.