Azov, Or Asov (in Turkish, Asak), a town of Russia, in the government of the Don Cossacks, on the left bank of the southern arm of the Don, about 20 m. from its mouth. The ancient Tanais lay some 10 m. to the north. In the 13th century the Genoese had a factory here which they called Tana. Azov was long a place of great military and commercial importance. Peter the Great obtained possession of it after a protracted siege in 1696, but in 1711 restored it to the Turks; in 1739 it was finally united to the Russian empire. Since then it has greatly declined, owing to the silting up of its harbour and the competition of Taganrog. Its population, principally engaged in the fisheries, numbered 25,124 in 1900.