a republic in N Europe, on the Baltic Sea: ceded to Russia by Sweden in 1809; gained independence in 1917; Soviet invasion successfully withstood in 1939–40, with the loss of Karelia; a member of the European Union. It is generally low-lying, with about 50 000 lakes, extensive forests, and peat bogs. Official languages: Finnish and Swedish. Religion: Christian, Lutheran majority. Currency: euro. Capital: Helsinki. Pop: 5 523 231 (2017 est). Area: 337 000 sq km (130 120 sq miles)