​DUX (Czech Duchcov), a town of Bohemia, Austria, 86 m. N.N.W. of Prague by rail. Pop. (1900) 11,921, three-fourths German. It is situated in the centre of an extensive and well-worked lignite deposit and manufactures glass, porcelain and earthenware. In Dux is a castle belonging to Count Waldstein, a kinsman of Wallenstein, which contains a picture gallery with two portraits of Wallenstein by Van Dyck, and a museum with a collection of arms and armour and several relics of the great general.