For example, we often say that the Shang Dynasty, the Zhou Dynasty, the Tang Dynasty, etc. are all dynasties, but the dynasties that survived are generally unified, and they have made brilliant achievements in national population, land area, social and economic development, culture and so on.

Countries are relatively small, such as the Zhou Dynasty, which is itself a enfeoffment system, and there are many countries below, such as Qi, Yan, Qin and so on. Although they all obey the leadership of the Zhou royal family, they are all independent countries.

Another example is the Three Kingdoms, Wei, Shu, Wu and Dong Han, which became the Jin Dynasty after reunification.

Later, I seemed to get used to it. The big one was given to North Korea and the small one to the country.

In fact, many times, different words are used only because of different contexts.