Poland, Pol. Polska, officially Republic of Poland, republic (2005 est. pop. 38,635,000), 120,725 sq mi (312,677 sq km), central Europe. It borders on Germany in the west, on the Baltic Sea and the Kaliningrad region of Russia in the north, on Lithuania, Belarus, and Ukraine in the east, and on the Czech Republic and Slovakia in the south. Warsaw is the capital and largest city.