a republic in SE Europe, on the Black Sea and the Sea of Azov: ruled by the Khazars (7th–9th centuries), by Ruik princes with the Mongol conquest in the 13th century, then by Lithuania, by Poland, and by Russia; one of the four original republics that formed the Soviet Union in 1922; unilaterally declared independence in 1990, which was recognized in 1991; annexation of Crimea by Russia in 2014 not recognized internationally, despite the mainly Russian population voting in favour of it in a disputed referendum. Consists chiefly of lowlands; economy based on rich agriculture and mineral resources and on the major heavy industries of the Donets Basin. Official language: Ukrainian; Russian is also widely spoken. Religion: Christian majority. Currency: hryvna. Capital: Kiev. Pop: 44 222 947 (2017 est). Area: 603 700 sq km (231 990 sq miles)