Khmelnytskyy (khmĕlnētˈskē) [key], Rus. Khmelmitsky, formerly Proskurov prəskŏrˈəf, city (1989 pop. 237,000), capital of Khmelnytskyy region, Ukraine, on the Southern Buh River. It is a rail terminus and highway hub and has food-processing (notably sugar-refining) plants and factories that produce machine tools, equipment for power stations, reinforced concrete items, and consumer goods. A 15th cent. Polish fortress town, it was seized by Cossacks in the 17th cent. It became part of Russia in the 1793 partition of Poland. Formerly called Proskurov, it was renamed in 1954 on the 300th anniversary of a treaty between the Russians and the Cossacks led by Bohdan Chmielnicki (Khmelnytskyy).