Aude (anc. Atax), a river and a department in the South of France. The former rises in the Eastern Pyrenees, and discharges itself through marshes into the Mediterranean about six miles from Narbonne, after a course of over 100 miles. Carcassonne is on its banks. The department is bounded N. by Herault and Tarn, E. by the Mediterranean, S. by Pyrenees Orientales, and W. by Ariege. It has an area of 2,341 square miles. The surface is mountainous, but intersected by rich valleys running north and south. Large lagoons extend along the coast. The agricultural products include wheat, maize, and other cereals, chestnuts, almonds, olives, wine in abundance, and honey, Antimony, manganese, copper, silver, iron, lead,. coal, marbles, jet, and lithographic stones are yielded in remunerative quantities, and there are some local manufactures. Carcassone, Narbonne, and Castelnaudary are the chief towns.