Batumi or Batum (butoom'), city (1990 est. pop. 136,609), capital of Adjarian Autonomous Republic, in W Georgia, on the Black Sea near the Turkish border. A major port and trade center, it is also the terminus of the Trans-Caucasian RR, the Crimean-Caucasian steamship line, and an oil pipeline. Batumi is an important petroleum-shipping port and has oil refineries, shipyards, and food-processing plants. Site of the ancient Greek colony of Batis, the city belonged to Georgia in the Middle Ages, fell to the Turks in the late 16th cent., and passed to Russia in 1878.