a structure or apparatus in which heat may be generated, as for heating houses, smelting ores, or producing steam.

a place characterized by intense heat

The volcano was a seething furnace.

( initial capital letter ) Astronomy . the constellation Fornax.

to heat (a metal piece) in a furnace.

noun

freezer

noun

boiler , calefactor , cinerator , cremator , forge , franklin stove , heater , heating system , incinerator , kiln , oil burner , smithy , stove , oven , reverberatory