A structure designed principally for (1) smelting ores, (2) melting previously smelted metals for casting or heating them for forging, and (3) firing pottery and other ceramic items. Furnaces in Bible times were constructed of brick or stone. Circular copper furnaces believed to date from the period of the Judges were found at Tell Qasileh on the northern outskirts of Tel Aviv-Yafo and at Tell Jemmeh (Tel Gamma), S of Gaza. These furnaces were equipped with large mud-brick flues designed to lead air into the fire chamber. Clay crucibles containing copper were set on top of the stone tiles that were placed on the ashes of the fire inside the furnace.

Daniel’s three faithful Hebrew companions were thrown into a fiery furnace by Nebuchadnezzar for refusing to bow down before the golden image the king had erected. (Da 3) Whether this was a special furnace constructed for such purpose or whether it was a furnace normally used for other common purposes, the record does not state.

The term “furnace” may also be used to refer to an “oven” for baking bread.​—Ho 7:4; Le 2:4.

Figuratively, Egypt, which confined Israel in a harsh yoke of slavery, is compared to an iron furnace. (De 4:20) Also, the outpouring of God’s anger upon the house of Israel is likened to the liquefying of metal in a furnace. (Eze 22:18-22) For other uses of the word for comparative or illustrative purposes, see Proverbs 17:3; 27:21; Psalm 12:6 (“smelting furnace”).​—See KILN; OVEN; REFINE, REFINER.