atmospheric pressure
Americannoun
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the pressure exerted by the earth's atmosphere at any given point, being the product of the mass of the atmospheric column of the unit area above the given point and of the gravitational acceleration at the given point.
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a value of standard or normal atmospheric pressure, equivalent to the pressure exerted by a column of mercury 29.92 inches (760 millimeters) high, or 1013 millibars (101.3 kilopascals).
noun
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The pressure at any location on the Earth, caused by the weight of the column of air above it. At sea level, atmospheric pressure has an average value of one atmosphere and gradually decreases as altitude increases.
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Also called barometric pressure
Closer Look
The weight of the air mass, or atmosphere, that envelopes Earth exerts pressure on all points of the planet's surface. Meteorologists use barometers to measure this atmospheric pressure (also called barometric pressure). At sea level the atmospheric pressure is approximately 1 kilogram per square centimeter (14.7 pounds per square inch), which will cause a column of mercury in a mercury barometer to rise 760 millimeters (30.4 inches). The pressure is frequently expressed in pascals, after the French mathematician and philosopher Blaise Pascal, who studied the transmission of pressure in confined fluids. Subtle variations in atmospheric pressure greatly affect the weather. Low pressure generally brings rain. In areas of low air pressure, the air is less dense and relatively warm, which causes it to rise. The expanding and rising air naturally cools, and the water vapor in the air condenses, forming clouds and the drops that fall as rain. In high pressure areas, conversely, the air is dense and relatively cool, which causes it to sink. The water vapor in the sinking air does not condense, leaving the skies sunny and clear.
Discover More
Normal atmospheric pressure at sea level is about fifteen pounds per square inch. (See barometer.)
Etymology
Origin of atmospheric pressure
First recorded in 1655–65
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
The title refers to the pressure inside a bottle of Champagne or Champagne-method sparkling wine: up to six times the average atmospheric pressure at sea level.
From The Wall Street Journal • Nov. 6, 2025
Barosinusitis is fairly common on flights or when scuba-diving because the atmospheric pressure around us can’t always equalize with the air pressure inside our sinuses.
From Los Angeles Times • Jun. 17, 2024
Cold fronts, or conditions after one, can cause falling temperatures, atmospheric pressure changes and gusty winds.
From Seattle Times • May 1, 2024
This process reduces the atmospheric pressure, lowering alcohol's boiling point and allowing the beer to be heated to a warm temperature to retain taste while evaporating the alcohol.
From BBC • Feb. 15, 2024
This was, in effect a wind gun driven by atmospheric pressure and where the piston replaced the bullet.
From "The Invention of Science" by David Wootton
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
