(uncountable, chemistry) Matter in a state intermediate between liquid and plasma that can be contained only if it is fully surrounded by a solid (or held together by gravitational pull); it can condense into a liquid, or can (rarely) become a solid directly.
A lot of gas had escaped from the cylinder
(countable, chemistry) A chemical element or compound in such a state.
The atmosphere is made up of a number of different gases
(uncountable) An inflammable gaseous hydrocarbon or hydrocarbon mixture (typically predominantly methane) used as a fuel, e.g. for cooking, heating or electricity generation.
Gas-fired power stations have largely replaced coal-burning ones.
(US) Methane or other waste gases trapped in one's belly as a result of the digestive process. My tummy hurts so bad, I have gas.
