- water in the gaseous state, esp when due to evaporation at a temperature below the boiling pointCompare steam
Examples from the Web for water vapour
Dew-point, the temperature at which the air is saturated with the water-vapour which it contains.The New Gresham Encyclopedia
We cannot say if, or to what extent, these clouds consist of water-vapour.The Story of Evolution
Every one knows that there is abundance of water-vapour in the atmosphere, but the question arises, How does it get there?
For each degree of temperature there is a certain amount of water-vapour which can be absorbed, and no more.
An immense amount of evaporation takes place from these mighty rivers, so that the air above them becomes laden with water-vapour.