Ukraine (Ukrayina) is a country in Eastern Europe. It lies at the northwest end of the Black Sea, with Russia to the east, Belarus to the north, Poland to the northwest, Slovakia and Hungary to the west, and Romania to the south west and south, with Moldova in between.
Most of the country (the central and eastern portions) was formerly a part of Russian Empire; after WWII, the entire country - known as the Ukrainian Soviet Socialist Republic - was a part of the Soviet Union. Ukraine is the second-largest country in Europe, albeit with a slightly declining population.
Understand
In English, the country is sometimes referred to with the definite article, "The Ukraine", a grammatically incorrect term usually applied to a region, rather than a political entity (e.g. the Baltics, the Caucasus, the West etc.) Since its establishment as an independent nation in 1991, the country is officially called simply "Ukraine," and this form should be used when refering to the country.
History
Ukrainian history is long and proud, with the inception of Kyivan (or Kievan) Rus as the most powerful state in Medieval Europe. While this state fell prey to Mongol conquest, the western part of Ukraine became part of the Polish-Lithuanian Commonwealth form the 14th until the 18th century, even modern Ukraine owes it a debt of sorts. A subsequent Ukrainian state was able to - in the face of pressure from the ascendant Muscovy - remain autonomous for more than a century, however the Russian Empire absorbed much of Ukraine in the 18th century, to the detriment of their culture and identity.