a former republic in central Europe: formed after the defeat of Austria-Hungary (1918) as a nation of Czechs in Bohemia and Moravia and Slovaks in Slovakia; occupied by Germany from 1939 until its liberation by the Soviet Union in 1945; became a people's republic under the Communists in 1948; invaded by Warsaw Pact troops in 1968, ending Dubček's attempt to liberalize communism; in 1989 popular unrest led to the resignation of the politburo and the formation of a non-Communist government. It consisted of two federal republics, the Czech Republic and Slovakia, which separated in 1993