late 14c., from Anglo-French vapour, Old French vapor "moisture, vapor" (13c., Modern French vapeur) and directly from Latin vaporem (nominative vapor) "a warm exhalation, steam, heat," of unknown origin. Vapors "fit of fainting, hysteria, etc." is 1660s, from medieval notion of "exhalations" from the stomach or other organs affecting the brain.
权威例句
1. The two principal combustion products are water vapor and carbon dioxide.
两种主要的燃烧产物是水蒸气和二氧化碳。
2. The car windows were fogged with vapor.
车窗上满是雾气。
3. When nitric acid is poured on copper, a brown vapor gives off.