Are various seas considered part of the oceans they are connected to?

Factual Questions
1

For example, is the Caribbean part of the Atlantic or is it just the Caribbean? What about the Mediterranean or the Gulf of Finland or the Black Sea?

Thanks,
Rob

2

If you ask me I have no problems with the Gulf of Finland and the Bothnian Bay being parts of the Baltic Sea, which is in itself part of the Atlantic.

3

According to the CIA, they are: https://www.cia.gov/library/publications/the-world-factbook/geos/zh.html

4

Like the question of what is an island and what is a continent this is just a matter of opinion and definition anyway.