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

The tower is bristling with high-tech instruments - sensors that track almost everything happening between the forest and the atmosphere: water vapor, carbon dioxide, sunlight, and essential nutrients like nitrogen and phosphorus.

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What Enceladus does is akin to a volcano hurling lava into space -- except the ejecta are plumes of water vapor and ice.

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Until now, scientists believed that heat loss was limited to the south pole, where geysers shoot water vapor and ice particles into space.

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Unlike fossil fuels, which emit planet-warming carbon, hydrogen simply produces water vapor when burned.

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Astronomers have produced the first three-dimensional map of a planet outside our solar system, revealing distinct temperature regions, including one so hot that water vapor breaks apart.

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