Czechoslovakia, Czech and Slovak Československo', former country in central Europe encompassing the historical lands of Bohemia, Moravia, and Slovakia. Czechoslovakia was formed from several provinces of the collapsing empire of Austria-Hungary in 1918, at the end of World War I. In the interwar period it became the most prosperous and politically stable state in eastern Europe. It was occupied by Nazi Germany in 1938–45 and was under Soviet domination from 1948 to 1989. On Jan. 1, 1993, Czechoslovakia separated peacefully into two new countries, the Czech Republic and Slovakia.