thanks for your reply Merry Christmas
I don't know if Wikipedia is a valid Wiki, but this is "Federation" according to it :
: foedus, foederis
, 'covenant'), also known as a federal state
, is a political entity characterized by a union
of partially self-governing states
or regions united by a central (federal) government. In a federation, the self-governing status of the component states, as well as the division of power between them and the central government, are typically constitutionally entrenched and may not be altered by a unilateral decision of the latter.
It is definitely different to United Nation, but it fit to the characteristic of USA model of government. Plus, according to Wiki, it is a union of states with a central Federal government above them.