This is the 8369th most frequent Polish word.
pietrusiewicz
"Pietrusiewicz" is a Polish surname and does not have a specific definition in English beyond being a family name.
'Pietrusiewicz' in this sentence is used as a proper noun, specifically a surname for formal addressing.
Czy spotkałeś już pana Pietrusiewicza?
Have you met Mr. Pietrusiewicz yet?
'Pietrusiewiczów' here refers to the plural form of the surname, indicating the entire family with this name.
Rodzina Pietrusiewiczów mieszka w Warszawie.
The Pietrusiewicz family lives in Warsaw.
'Pietrusiewicz' is employed to refer informally to a single individual with this surname.