Busto Arsizio, a town of Lombardy, Italy, in the province of Milan, 21 m. N.W. by rail from the town of Milan. Pop. (1901) 19,673. It contains a fine domed church, S. Maria di Piazza, built in 1517 after the designs of Bramante: the picture over the high altar is one of Gaudenzio Ferrari's best works. The church of S. Giovanni Battista is a good baroque edifice of 1617; by it stands a fine 13th-century campanile. Busto Arsizio is an active manufacturing town, the cotton factories being especially important. It is a railway junction for Novara and Seregno.