What are the signs that underlie the division of the earth into parts? What is the difference between

What are the signs that underlie the division of the earth into parts? What is the difference between parts of the world and continents?

The division of the world into parts of the world and continents is based on different principles. Parts of the world are of more cultural and historical significance. This can be understood from the example of Asia and Europe, which are on a single continent, but represent separate parts of the world. The thing is that since ancient times the peoples of these parts have been very different from each other in behavior, languages, etc.
But the mainland is a geographical concept, and means a single large piece of land. There are only six continents and parts of the world on our planet.