water vapor

noun

1. a dispersion, in air, of molecules of water, especially as produced by evaporation at ambient temperatures rather than by boiling. Compare steam ( def 2 ).

water vapor

1. Water in its gaseous state, especially in the atmosphere and at a temperature below the boiling point. Water vapor in the atmosphere serves as the raw material for cloud and rain formation. It also helps regulate the Earth's temperature by reflecting and scattering radiation from the Sun and by absorbing the Earth's infrared radiation.
2. See also vapor

Word History and Origins

Origin of water vapor¹

First recorded in 1875–80

Example Sentences

Carbon dioxide is one of the chief anthropogenic greenhouse gases that contributes to climate change; the others are methane, water vapor, nitrous oxide and fluorinated gases.

From Salon

These particles, in turn, grow over time and then serve as condensation nuclei for water vapor -- they thus play an important role in cloud formation in the tropics.

From Science Daily

La Niña seasons typically produce large numbers of atmospheric rivers, or narrow bands of concentrated water vapor in the sky that act like rivers in the sky.

From Salon

The researchers examined the thermal performance of a TCM reactor powered by strontium chloride, which gives off heat as it reacts with water vapor in the air.

From Science Daily

Firstly, water vapor interferes and overlaps with the absorption spectra of many gases in the standard infrared ranges normally used for detection.

From Science Daily