Federalism
From the Simple English Wikipedia, the free encyclopedia that anyone can change
Federalism is a political philosophy in which a group of people are bound together, with a governing head. In federalism, the authority is divided between the head (for example the central government of a country) and the political units governed by it (for example the states or provinces of the country).
Currently, several countries in the world have a federal government; examples are United States of America, Canada, Switzerland and Austria. The European Union can be called a sort of federal government as well.
In other words Federalism is a system of government in which power is divided between a central authority and various constituent units of the country.