气体

气体 (qì tǐ) refers to a state of matter that has no fixed shape or volume and can expand freely. It differs from liquids and solids in its ability to spread out and fill any container it occupies.

The character 气 (qì) originally meant 'air' or 'spirit,' and 体 (tǐ) means 'body' or 'substance.' Together, they describe a physical substance in the gaseous state, often used in scientific contexts.

Gas is commonly encountered in daily life, such as in cooking (natural gas), medical settings (oxygen tanks), and environmental discussions (greenhouse gases). Understanding 气体 is essential for studying chemistry or physics in Chinese.