Cossacks (Ukrainian:козаки́, koza'ky, Russian:казаки́, kaza'ki) are a group of predominantly East Slavic-speaking people who became known as members of democratic, self-governing, semi-military communities, predominantly located in Russia and in Ukraine. They inhabited sparsely populated areas and islands in the lower Dnieper, Don, Terek, and Ural river basins and played an important role in the historical and cultural development of both Russia and Ukraine.