Titular nation

The titular nation is the single dominant ethnic group in a particular state, typically after which the state was named. The term was first used by Maurice Barrès in the late 19th century.

Soviet Union

The notion was used in the Soviet Union to denote nations that give rise to titles of autonomous entities within the union: Soviet republics, autonomous republics, autonomous regions, etc., such as Byelorussian SSR for Belarusians.
For an ethnos to become a Soviet titular nation, it had to satisfy certain criteria in terms of the amount of population and compactness of its settlement. The language of a titular nation was declared an additional official language of the corresponding administrative unit.

China

The People's Republic of China government has adopted some of the principles behind this Soviet concept in its ethnic minority policy—see Autonomous administrative divisions of China.

Yugoslavia

The federal republics of Socialist Yugoslavia were perceived as nation-states of the constitutional peoples. After the breakup of Yugoslavia, only Bosnia and Herzegovina was not defined in its constitution as a nation-state of its titular nation.