What is the relationship between countries?

A country with a monarchy and subordinate governors is called an empire.

A kingdom with a principality but no kingdom under a monarchy is called a kingdom.

An independent principality without a kingdom is called Grand Duchy (there can be Empire, Grand Duchy and Wang Guoping).

An independent sovereign entity grants part of its sovereignty to the central government to form a sovereign entity called Federation/Confederacy.

According to the amount and degree of partial sovereignty granted. If the degree of granting is deep, military and diplomatic sovereignty is granted to the central government, which is called confederation; if the degree of granting is shallow, it is only a nominal union, which is called confederation.

The modern Commonwealth is actually a confederation, not a nominal federation.

The EU is also a confederation.

The United States is just a name, not a national system. It can be a federal system or a confederation system. Federations such as the United States of America and the United Arab States.

* * * and countries, * * and countries refer to countries that implement the * * * and system. The so-called harmony system is the opposite of monarchy. Simply put, as long as it is not a monarchy, it is a * * and institutional country.

Corresponding to federalism is unitary system.

Federalism is a country in which several sovereign entities grant partial sovereignty to the central government, while unitary system is a country in which the central government grants partial sovereignty to local governments.

So your concepts don't actually correspond to each other, and many concepts overlap.