vapor
Americannoun
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vapors
plural
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a visible exhalation, such as fog, mist, steam, smoke, or noxious gas, diffused through or suspended in the air.
The vapors rising from the bogs smelled muddy.
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Physics. a gas at a temperature below its critical temperature.
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a substance converted into a gaseous state for technical or medicinal uses.
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a combination of gaseous particles of a substance and air.
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Archaic. vapors,
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harmful exhalations formerly supposed to be produced within the body, especially in the stomach.
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mental or physical illness, such as depression or hypochondria, formerly supposed to result from such exhalations, especially in women.
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Often Facetious. the vapors. a feeling of being overwhelmed with strong emotion.
That guy gives the press the vapors every time he announces a new project.
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Archaic.
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a strange, senseless, or fantastic notion.
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something insubstantial or transitory.
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verb (used with object)
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vapors,
present (3rd person singular)
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vapored,
past participle, past
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vaporing
present participle
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to cause to rise or pass off in, or as if in, vapor; vaporize.
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Archaic. to affect with the vapors; depress.
verb (used without object)
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vapors,
present (3rd person singular)
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vapored,
past participle, past
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vaporing
present participle
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to rise or pass off in the form of vapor.
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to emit vapor or exhalations.
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to talk or act grandiloquently, pompously, or boastfully; bluster.
noun
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The gaseous state of a substance that is normally liquid or solid at room temperature, such as water that has evaporated into the air.
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See more at vapor pressure See also water vapor
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A faintly visible suspension of fine particles of matter in the air, as mist, fumes, or smoke.
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A mixture of fine droplets of a substance and air, as the fuel mixture of an internal-combustion engine.
Usage
The words vapor and steam usually call to mind a fine mist, such as that in the jet of water droplets near the spout of a boiling teakettle or in a bathroom after a shower. Vapor and steam, however, refer to the gaseous state of a substance. The fumes that arise when volatile substances such as alcohol and gasoline evaporate, for example, are vapors. The visible stream of water droplets rushing out of a teakettle spout is not steam. As the gaseous state of water heated past its boiling point, steam is invisible. Usually, there is a space of an inch or two between the spout and the beginning of the stream of droplets. This space contains steam. The steam loses its heat to the surrounding air, then falls below the boiling point and condenses in the air as water droplets. All liquids and solids give off vapors consisting of molecules that have evaporated from the substance. In a closed system, the vapor pressure of these molecules reaches an equilibrium at which the substance evaporates from the liquid (or solid) and recondenses on it in equal amounts.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Participles
Conjugated Forms
Present
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vaporsimple
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vaporssimple
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have vaporedperfect
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has vaporedperfect
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am vaporingprogressive
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are vaporingprogressive
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is vaporingprogressive
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have been vaporingperfect progressive
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has been vaporingperfect progressive
Past
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vaporedsimple
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had vaporedperfect
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was vaporingprogressive
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were vaporingprogressive
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had been vaporingperfect progressive
Future
Etymology
Origin of vapor
First recorded in 1325–75; Middle English vapour, from Latin vapor “steam,” of uncertain origin; akin to vapidus vapid ( def. ) and vappa “wine that has gone flat”; perhaps cognate with Greek kapnós “smoke” ( see acapnia ( def. ))
Explanation
When something that is normally liquid — like water — becomes a visible, gas-like substance floating in the air, it's a vapor. The fog that often settles across your town in the mornings is one kind of vapor. Mist is also a vapor, as is your frozen breath when you can see it on a cold winter day. The Latin root word is vaporem, "exhalation, steam, or heat."
Vocabulary lists containing vapor
The Water Cycle - Introductory
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Earth Science - Middle School
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The Water Cycle - Middle School and High School
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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.
See Examples For:
The coating encourages more droplets to appear as water vapor condenses while also making it easier for those droplets to leave the surface.
From Science Daily ● Aug. 23, 2026
He said it is likely that vapor could be present beneath homes, depending on the flow of groundwater.
From Los Angeles Times ● Aug. 11, 2026
“Certainly some of those homes will have some type of vapor intrusion risk, really the only way to know for sure is to go test the home,” he said.
From Los Angeles Times ● Aug. 11, 2026
The method captures the balance between water vapor produced as air rises and water vapor removed as it condenses onto droplets.
From Science Daily ● Aug. 1, 2026
His surroundings were not hidden by cloudy vapor; rather the cloudy vapor had not yet formed into surroundings.
From "Harry Potter and the Deathly Hallows" by J.K. Rowling
Did he inhale too deeply the vapors of power?
From Slate ● Jul. 13, 2026
Healthcare Agency said it did not dispute statements that vapors were released from the pressurized tank on May 21.
From Los Angeles Times ● Jun. 6, 2026
In response to questions from The Times, the Orange County Healthcare Agency said it did not dispute statements that chemical vapors were released from the pressurized tank on May 21.
From Los Angeles Times ● Jun. 4, 2026
Authorities said if people are exposed to vapors they need to find fresh air or receive oxygen if they have trouble breathing.
From The Wall Street Journal ● May 24, 2026
The dungeon was, most unusually, already full of vapors and odd smells.
From "Harry Potter and the Half-Blood Prince" by J.K. Rowling
The Tribune must have more "kick," so it vapored about "a few daring New Yorkers" venturing into the "far West," discovering Chicago and telling their friends about it.
From Time Magazine Archive
High over all this billowing and peaking tower the Pitons of Carbet, gem-violet through the vapored miles,—the tallest one filleted with a single soft white band of cloud.
From Two Years in the French West Indies by Lafcadio Hearn
He raged and vapored and threatened on the floor of the House.
From A History of the Four Georges and of William IV, Volume III by Justin McCarthy
The suck of fresh air under pressure, vapored like steam, whirled around them in gusts, and the water oozed and rippled beside 109 their feet as they went forward.
From The Plunderer by Douglas Duer
Mackenzie vapored and complained of others, formed plans one hour to change the next, and demonstrated the weakness of his shallow nature.
From The Narrative of Gordon Sellar Who Emigrated to Canada in 1825 by Gordon Sellar
The press was busy vaporing upon the significance of a de Valera free to roam the Free State.
From Time Magazine Archive
Apparently the only contribution Fiver could make was this beetle-spirited vaporing.
From "Watership Down: A Novel" by Richard Adams
They became very insolent and boastful, and would sharpen their knives and tomahawks upon the door-sills of the colonists, vaporing in mysterious phrase of the great deeds they were about to perform.
From King Philip Makers of History by John S. C. (John Stevens Cabot) Abbott
Alone he faced the roystering Morton at Merrymount, unarming that vaporing rebel and putting his riotous colony upon its good behavior.
From Great Men and Famous Women. Vol. 1 A series of pen and pencil sketches of the lives of more than 200 of the most prominent personages in History by Charles F. (Charles Francis) Horne
Yet Paul did not waste all his hours in this idle vaporing, nor in the pleasures of the table.
From History of the Reign of Philip the Second, King of Spain, Vols. 1 and 2 by William Hickling Prescott
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.
