a strongly fortified town of France, department of Pas de Calais, situated on a rock above the river Brette, 16 miles N.N.W. of Arras. Its castle was fortified by Vauban. It has a tribunal of primary jurisdiction, a communal college, a Gothic church, two hospitals, and manufacturers of linen, cloth, beer, &c. The trade, chiefly in grain, cheese, linen, and oil, is facilitated by the canal which unites the Lave with the Lys. It was taken by the allied forces in 1710, and restored to France by the treaty of Utrecht. Pop. (1851) 7150. Area of the arrondissement of this name, 360 square miles; pop. 130,078.