A
national trade union center is a federation or confederation of
trade unions in a single
country. Nearly every country in the world has a national trade union center, and many have more than one. When there is more than one national center, it is often because of
ideological differences—in some cases long-standing historic differences. In some regions, such as the
Nordic countries, different centers exist on a sectoral basis, for example for
blue collar workers and
professionals.