noun

• (historical) A former country on the Balkan Peninsula, made up of the now-independent nations of Bosnia and Herzegovina, Croatia, North Macedonia, Montenegro, Serbia and Slovenia; it disintegrated in the 1990s.
• (historical) The Federal Republic of Yugoslavia, a rump state formed by Serbia and Montenegro after 1992.
• (historical, nonstandard, by extension) Serbia and Montenegro, after 2003 until 2006, when it disintegrated.