gas
Matter in an intermediate state between liquid and plasma that can be contained only if it is fully surrounded by a solid (or in a bubble of liquid, or held together by gravitational pull); it can condense into a liquid, or can (rarely) become a solid directly by deposition.
Example
“A lot of gas had escaped from the cylinder.”
Other meanings
A flammable gaseous hydrocarbon or hydrocarbon mixture used as a fuel, e.g. for cooking, heating, electricity generation or as a fuel in internal combustion engines in vehicles, especially natural gas.
A chemical element or compound in such a state.
“The atmosphere is made up of a number of different gases.”
Example sentences
Word history
From Ancient Greek "χάος" (chasm, void, empty space).
Where this comes from
This definition is adapted from “gas” on Wiktionary, by its contributors; example sentences are from Tatoeba, credited to their authors above, published under CC BY-SA 4.0. This page is published under the same licence.