address. Tsar also Czar , Tzar , Csar , and Zar (Russian: царь ) (English pronunciation [zar]; Russian pronunciation is [ʦarʲ]) (Russian tsar from Latin Caesar "hairy"). (historical) Title of a Southern Slav ruler as in Bulgaria (913-1018, 1185-1422, and 1908-1946) and Serbia (1346-1371). (historical) Title for the emperor of Russia