Federal Republic of Yugoslavia n 1: a mountainous republic in southeastern Europe bordering on the Adriatic Sea; formed from two of the six republics that made up Yugoslavia until 1992; Serbia and Montenegro were known as the Federal Republic of Yugoslavia until 2003 when they adopted the name of the Union of Serbia and Montenegro [syn: {Serbia and Montenegro}, {Union of Serbia and Montenegro}, {Yugoslavia}, {Federal Republic of Yugoslavia}, {Jugoslavija}]