Adda (anc. Addua), a river of N. Italy, a tributary of the Po. It rises in the Rhaetian Alps, flows S. W., S., and S. E. through the Valtellina and Lombardy, and the lakes of Como and Lecce, and enters the Po about 8 m. W. of Cremona. Its course is about 80 m. Lodi, the scene of one of Bonaparte's early triumphs, and Cassano, at which Moreau was defeated in 1799, are on its banks.