This is the 8763rd most frequent Polish word.
rostkowski
"Rostkowski" is a Polish surname and does not have a standalone definition in English.
In this sentence, 'Rostkowski' is used as a proper noun referring to the author's surname.
Rostkowski napisał ciekawą książkę o historii Polski.
Rostkowski wrote an interesting book about the history of Poland.
Here, 'Rostkowski' represents the signature or identification of the artist, indicating their name.
W muzeum widziałem obraz podpisany Rostkowski.
In the museum, I saw a painting signed Rostkowski.
'Rostkowski' is used as a surname to identify a person in a class setting.