flue
1 Americannoun
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a passage or duct for smoke in a chimney.
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any duct or passage for air, gas, or the like.
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a tube, especially a large one, in a fire-tube boiler.
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Music.
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Also called windway. a narrow slit in the upper end of an organ pipe through which the air current is directed.
noun
noun
noun
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a shaft, tube, or pipe, esp as used in a chimney, to carry off smoke, gas, etc
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music the passage in an organ pipe or flute within which a vibrating air column is set up See also flue pipe
noun
noun
noun
Other Word Forms
Etymology
Origin of flue1
First recorded in 1555–65; earlier flew; of uncertain origin; perhaps from Old English flēwsa “a flowing, flux,” the form flews being taken as plural
Origin of flue2
First recorded in 1580–90; of uncertain origin; perhaps from Old English flug- (in flugol “swift, fleeting”); perhaps from Flemish Dutch vluwe, from French velu “hairy, downy”; see also velvet ( def. )
Origin of flue3
First recorded in 1350–1400; Middle English flue, flowe, flew, from Middle Dutch vl(o)uwe “fishing net”; akin to Old English flōwan flow ( def. )
Explanation
When smoke flows out of a chimney, it moves through a narrow opening called a flue. Before you light a fire in the fireplace, make sure the flue is open! Don't mistake flue for its homonym, flu — rather than an illness, a flue is a duct or pipe that's connected to a stove, heater, furnace, or fireplace. Smoke or gas can flow freely through the flue, which allows the appliance to work properly and vents any nasty exhaust away from people. Experts disagree about the origin of this word, but many trace it back to a Germanic root meaning "to flow."
Vocabulary lists containing flue
"The Veldt" by Ray Bradbury
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Cat's Cradle
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By the Roots: Fluere: to flow (flu-)
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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.
A generation or so ago, an open stair like this would have been restricted to two stories to ensure it didn’t act as a flue during a fire.
From The Wall Street Journal • Mar. 20, 2026
However, sounds from things like flue organ pipes or flutes, which are propagated through air, would be pitched higher than Earth.
From Salon • Jun. 3, 2025
Technicians either use an existing opening or create a temporary hatch through which the flue - typically made of a metal such as iron or steel - is inserted.
From BBC • May 4, 2025
California health officials are investigating a possible case of H5N1 bird flue infection in a person who had contact with dairy cows in the Central Valley.
From Los Angeles Times • Oct. 3, 2024
Smoke was suddenly everywhere, like the air in a living room where someone forgets to open the flue before starting a fire.
From "Newjack: Guarding Sing Sing" by Ted Conover
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.
