Pig-iron
Iron in the form of an oblong bar, so called from having been run from a central or main channel designated the sow, which connects with the tap-hole of the blast-furnace, and may be directed to any part of the sand floor of the casting-house, the pigs being branches from the same. According to the fracture, pig iron is classified as gray, mottled, and white iron. See CAST-IRON; GRADES OF PIG-IRON.