water vapor

noun

1. a dispersion, in air, of molecules of water, especially as produced by evaporation at ambient temperatures rather than by boiling.

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

As the smoke rises, water vapor in the air condenses at high altitudes, creating what is known as a pyrocumulus cloud, or fire cloud.

From Los Angeles Times

He said such storms, which roll in from the Pacific Ocean carrying massive amounts of water vapor, would typically be on a larger scale.

From Los Angeles Times

Hydrogen is a promising source of energy that produces water vapor instead of carbon dioxide as its byproduct, which proponents say could be used to power hard-to-decarbonize industries such as steel production, manufacturing and transportation.

From Los Angeles Times

Depending on the type of rocket fuel used, launches produce nitrogen oxides, chlorine, black carbon particles, water vapor, carbon monoxide and carbon dioxide — and no propellant avoids creating of some kind of emissions.

From Salon

To learn this, scientists at the University of Arkansas recreated the arid conditions which exist on Mars, in particular the average temperature of −70 °C and very low water vapor content.

From Salon