This is the 17th most frequent Bulgarian word.
което
"Което" means "which" or "that" (relative pronoun).
Here, 'което' is used to introduce additional information about a statement or event mentioned previously.
Бях изненадан от случилото се, което не очаквах.
I was surprised by what happened, which I didn’t expect.
In this case, 'което' functions as a relative pronoun pointing to a specific detail or idea expressed just before it.
Не разбрах точно това, което каза.
I did not understand exactly what you said.
Here, 'което' is used as a relative pronoun to refer to an antecedent (the book) connecting the main clause to the subordinate clause.