furnace

noun

fur·​nace ˈfər-nəs 

: an enclosed structure in which heat is produced (as for heating a house or for reducing ore)

Examples of furnace in a Sentence

Recent Examples on the Web

Replacing a gas furnace with an electric heat pump, which moves heat instead of generating it through combustion, cuts about 1,830 pounds of carbon dioxide per household per year. —Aya Diab, Los Angeles Times, 18 Feb. 2026

According to a preliminary investigation, four people were in the basement of the church when the furnace activated, triggering an explosion. —Nadine El-Bawab, ABC News, 17 Feb. 2026

The organization would prefer the use of direct reduction furnaces, which GARD members claim is more efficient than blast furnaces and could be used to create iron for steelmaking in Northwest Indiana. —Maya Wilkins, Chicago Tribune, 16 Feb. 2026

Here's why Klossner uses a mix of electric and gas to heat her home, with a furnace that runs on electric, and a water tank and stove that run on natural gas. —Jeanine Santucci, USA Today, 15 Feb. 2026

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 *g^whr̥-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 *g^wher- "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

Phrases Containing furnace

• blast furnace
• reverberatory furnace

Rhymes for furnace

• externus

Kids Definition

furnace

noun

fur·​nace ˈfər-nəs 

: an enclosed structure in which heat is produced (as for heating a house or melting metals)