TORREFAC'TION, n. [L.torrefacio; torridus and facio.]

1. The operation of drying by a fire.

2. In metallurgy, the operation of roasting ores.

3. In pharmacy, the drying or roasting of drugs on a metalline plate, placed over or before coals of fire, till they become friable to the fingers, or till some other desired effect is produced.