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 answer may reveal that the biggest opportunity to lower utility bills isn’t buying a more efficient furnace or air conditioner. — Brynn Cooksey, Forbes.com, 6 Aug. 2026 To extract valuable metals such as silver, lead, copper, and zinc from the hard rock, the ore was crushed and then smelted in a furnace using intense heat. — ABC News, 27 July 2026 For example, a home might have a furnace for heat but lack a whole-home air conditioner. — Alora Bopray, USA Today, 24 July 2026 Their next major undertaking is installing an outdoor wood boiler system and radiators throughout the house, which currently doesn’t have a furnace. — Ashley Vega, PEOPLE, 24 July 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 13 Aug. 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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