furnace
Americannoun
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a structure or apparatus in which heat may be generated, as for heating houses, smelting ores, or producing steam.
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a place characterized by intense heat.
The volcano was a seething furnace.
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Astronomy. Furnace, the constellation Fornax.
verb (used with object)
noun
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an enclosed chamber in which heat is produced to generate steam, destroy refuse, smelt or refine ores, etc
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a very hot or stifling place
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Etymology
Origin of furnace
First recorded in 1175–1225; Middle English furneis, furnais, from Old French fornais, fournais, from Latin fornāc- (stem of fornāx “kiln, oven”), akin to formus “warm”
Explanation
A furnace is an appliance that heats houses and buildings by burning fuel or circulating hot water. Your furnace might rumble in the basement, sending heat up through your house's radiators. Most houses in cold climates have a furnace, to warm their rooms during the chilly months of the year. Furnaces also have industrial uses, like burning trash or extracting ore from metal. If someone says, "It's as hot as a furnace in this classroom!" they mean that it's extremely hot. Furnace comes from the Old French fornaise, "oven," with the Latin root word fornacem, "oven or kiln."
Vocabulary lists containing furnace
Mockingbird
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Unit 4: Powerful Openings
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Unit 1, Words to Know
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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.
Instead of working with a massive furnace, participants use small torches, making the process feel more approachable and easier to control.
From Salon • Jun. 11, 2026
As a musician, the sounds escaping his horn seemed to rise from some far larger, internal furnace of intellectual and spiritual restlessness.
From The Wall Street Journal • May 26, 2026
The furnace, burning at more than 1,000C, is something he has learned to live with.
From BBC • Apr. 28, 2026
Maybe the furnace needs replacing, a medical bill arrives out of the blue, or an education expense catches you by surprise.
From MarketWatch • Apr. 23, 2026
It was bewildering to find them so many miles and centuries out of Egypt, and so far from the fiery furnace.
From "The Fire Next Time" by James Baldwin
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.
