BUSTO ARSIZIO, urban district, Italy, province of Milan, 21m. N.W. of Milan. Pop. (1921) 24,057 (town), 27,568 (com mune). The fine domed S. Maria di Piazza (1517) is from Bramante's designs: the picture over the high altar is one of Gaudenzio Ferrari's best works. Busto Arsizio is an active manu facturing town with cotton factories, etc.