vapor
Americannoun
-
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.
-
Physics. a gas at a temperature below its critical temperature.
-
a substance converted into a gaseous state for technical or medicinal uses.
-
a combination of gaseous particles of a substance and air.
-
Archaic. vapors,
-
harmful exhalations formerly supposed to be produced within the body, especially in the stomach.
-
mental or physical illness, such as depression or hypochondria, formerly supposed to result from such exhalations, especially in women.
-
-
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.
-
Archaic.
-
a strange, senseless, or fantastic notion.
-
something insubstantial or transitory.
-
verb (used with object)
-
to cause to rise or pass off in, or as if in, vapor; vaporize.
-
Archaic. to affect with the vapors; depress.
verb (used without object)
-
to rise or pass off in the form of vapor.
-
to emit vapor or exhalations.
-
to talk or act grandiloquently, pompously, or boastfully; bluster.
noun
-
The gaseous state of a substance that is normally liquid or solid at room temperature, such as water that has evaporated into the air.
-
See more at vapor pressure See also water vapor
-
A faintly visible suspension of fine particles of matter in the air, as mist, fumes, or smoke.
-
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
-
vaporsimple
-
vaporssimple
-
have vaporedperfect
-
has vaporedperfect
-
am vaporingprogressive
-
are vaporingprogressive
-
is vaporingprogressive
-
have been vaporingperfect progressive
-
has been vaporingperfect progressive
Past
-
vaporedsimple
-
had vaporedperfect
-
was vaporingprogressive
-
were vaporingprogressive
-
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
Looking to grow your vocabulary? Check out this interactive, curated word list from our team of English language specialists at Vocabulary.com – one of over 17,000 lists we've built to help learners worldwide!
Earth Science - Middle School
Interested in learning more words like this one? Our team at Vocabulary.com has got you covered! You can review flashcards, quiz yourself, practice spelling, and more – and it's all completely free to use!
The Water Cycle - Middle School and High School
Want to remember this word for good? Start your learning journey today with our library of interactive, themed word lists built by the experts at Vocabulary.com – we'll help you make the most of your study time!
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:
Those observations detected water vapor and methane, adding further evidence that the object was a planet and revealing more details about its atmosphere.
From Science Daily ● Jul. 23, 2026
Walking through the space, I passed between the steam room and saunas of the traditional vapor and infrared variety.
From The Wall Street Journal ● Jun. 9, 2026
The resulting vapor then traveled through a tube in which temperatures could be carefully controlled as the material cooled.
From Science Daily ● Jun. 3, 2026
One tank on Thursday did release vapor after the tank experienced an increase in temperature.
From Los Angeles Times ● May 23, 2026
As Piper watched, eight of the nymphs dissolved into vapor and floated upward.
From "The Mark of Athena" by Rick Riordan
Did he inhale too deeply the vapors of power?
From Slate ● Jul. 13, 2026
They were a toxic organization coasting on a grand arena and the vapors of memories.
From The Wall Street Journal ● Jun. 14, 2026
“There was no contamination, there were no fumes, there were no vapors that came from this incident. There was no leak.”
From Los Angeles Times ● May 26, 2026
Southern California is bracing for a possible leak or explosion of toxic vapors from a damaged tank that has forced thousands of people to evacuate.
From The Wall Street Journal ● May 24, 2026
“If you heat liquid, it can turn into a gas. Some of the poisonous liquid in the caldron has become the poisonous vapors that are holding the liquid.”
From "Aru Shah and the End of Time" by Roshani Chokshi
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
The warriors were evidently baffled by these precautions, and, having smoked their pipe, and vapored off their valor, took their departure.
From Astoria, or, anecdotes of an enterprise beyond the Rocky Mountains by Irving, Washington
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 McCarthy, Justin
"She needn't to have done that about her piano," vapored Mr. Vertrees.
From The Turmoil, a novel by Tarkington, Booth
"I don't care so much about the money," vapored Sube; "but I'm goin' to be awful tired when I get through cuttin' the lawn."
From Sube Cane by Partridge, Edward Bellamy
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
The little man, with all his vaporing, his windy boasts, his general utter worthlessness, had at bottom a grain of something genuine which keen Ike Byloe lacked.
From Lippincott's Magazine, Vol. 22, September, 1878 by Various
I appear to be vaporing in a spirit of vainglory; and yet it is under the mere coercion of 'salva necessitas' that I am surprised into this unparalleled instance of activity.
From The Atlantic Monthly, Volume 12, No. 71, September, 1863 by Various
One might well excuse Walpole if he became sometimes a little impatient of the attitudinizing and the vaporing of the Patriots.
From A History of the Four Georges, Volume II by McCarthy, Justin
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.
