noun
vapor
VAY-pur/ˈveɪpər/
A substance in the air as a gas or fine droplets.
Violet iodine vapor fills the space above the dark crystals.

Etymology
Latin vapor meant a warm exhalation or steam. The scientific sense makes that everyday image more precise: a substance in gaseous form rather than its usual liquid or solid state.
In context
burn jet fuel they produce exhaust that exhaust is mostly hot water vapor that also contains carbon dioxide trace amounts of sulfur nitrogen
More examples
- The paint releases harmful vapors as it dries.
- A thin cloud of vapor rises from the steaming soup.
- As the alcohol evaporates, it turns into vapor.
Forms
vapor · vapors
vaporize verb — To turn a substance into gas.
vaporous adjective — Consisting of or resembling gas or mist.