What is the different between superordinate clause and main clause?

The main clause is a clause that can form a complete sentence standing alone, having a subject and a predicate, and on which depend other clauses, it can never be subordinate clause, while a superordinate clause can be in the same time superordinate and subordiante at the same time.

1-main clause/superordinate (is super because the second depends on it)

2- subordinate/superordinate clause,

3- subordinate clause, which depends on dhe second, that's why the second one is also superordinated.