A tuyere's a tube, nozzle or pipe through which air's blown into a furnace or hearth. Air or oxygen's injected into a hearth under pressure from bellows or a blast engine or other devices. This causes the fire to be hotter in front of the blast than it'd otherwise have been, enabling metals to be smelted or melted or made hot enough to be worked in a forge. This applies to any process where a blast's delivered under pressure to make a fire hotter. The term (like many technical terms relating to… (More on Tuyere)