furnace

noun

fur·​nace ˈfər-nəs How to pronounce furnace (audio)
: an enclosed structure in which heat is produced (as for heating a house or for reducing ore)

Examples of furnace in a Sentence

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Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
The cost to replace a furnace averages $4,745 and may reach $7,000. —Lee Wallender, The Spruce, 5 Feb. 2026 The sound reminds me of the ducts in my home heating system that make noise when the furnace comes on. —John Paul, The Providence Journal, 30 Jan. 2026 Roe Minicozzi said she's had to bundle up and stay close to the portable radiator in her South Philadelphia home after her furnace stopped working nearly a week ago. —Joshua Sidorowicz, CBS News, 30 Jan. 2026 This advice only applies to traditional furnaces, though, because heat pumps and radiant heat take too long to reheat your home. —Brandee Gruener, Southern Living, 29 Jan. 2026 See All Example Sentences for furnace

Word History

Etymology

Middle English fourneyse, fornes, furneis "oven, kiln, furnace," borrowed from Anglo-French furneis, fornays, fornaise (continental Old French forneis —attested once as masculine noun— fornaise, feminine noun), going back to Latin fornāc-, fornāx (also furnāx) "furnace, oven, kiln (for heating baths, smelting metal, firing clay)," from forn-, furn-, base of furnus, fornus "oven for baking" + -āc-, -āx, noun suffix; forn- going back to Indo-European *gwhr̥-no- (whence also Old Irish gorn "piece of burning wood," Old Russian grŭnŭ, gŭrnŭ "cauldron," Russian gorn "furnace, forge," Bosnian-Croatian-Serbian gŕno "coals for heating iron at a smithy," Sanskrit ghṛṇáḥ "heat, ardor"), suffixed derivative of a verbal base *gwher- "become warm" — more at therm

Note: The variation between -or-, the expected outcome of zero grade, and -ur- in Latin has been explained as reflecting a rural/dialectal change of o to u, borrowing from Umbrian, or the result of a sound change of uncertain conditioning; see most recently Nicholas Zair, "The origins of -urC- for expected -orC- in Latin," Glotta, Band 93 (2017), pp. 255-89.

First Known Use

13th century, in the meaning defined above

Time Traveler
The first known use of furnace was in the 13th century

Phrases Containing furnace

Rhymes for furnace

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Cite this Entry

“Furnace.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/furnace. Accessed 16 Feb. 2026.

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Kids Definition

furnace

noun
fur·​nace ˈfər-nəs How to pronounce furnace (audio)
: an enclosed structure in which heat is produced (as for heating a house or melting metals)

More from Merriam-Webster on furnace

Nglish: Translation of furnace for Spanish Speakers

Britannica.com: Encyclopedia article about furnace

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