an arrondissement of the department of the Seine and Oise, in France, extending over 478 square miles, divided into seven cantons and 175 communes, with 87,500 inhabitants. The capital is the city of the same name, situated at the junction of the river Bierme with the Oise. It contains 800 houses, and 5400 inhabitants. The church of St Martin's, a fine Gothic structure, forms its most distinguished ornament. It is celebrated for its veal, which is sent to Paris. Long. 12. 1. E. Lat. 49. 3. N.