气体的英文是 gas。它的来源是拉丁语的 "chaos" 或 "chasmus"，原意是指混沌和裂缝。

例句：

氧气是一种常见的气体。Oxygen is a common gas.

气体在压力作用下会变得更小。Gases become smaller under pressure.

气体的浓度会影响它的化学性质。The concentration of a gas can affect its chemical properties.