This is the 8186th most frequent Polish word.
olkuszu
"Olkuszu" is the locative case of "Olkusz," which refers to a town in Poland.
In this sentence, 'Olkusz' is used as a proper noun, referring to the town itself as a location.
Odwiedziłem Olkusz w zeszłym roku i bardzo mi się tam podobało.
I visited Olkusz last year and I really liked it there.
Here, 'Olkusza' represents the origin of the person, indicating a connection to the town.
Mój przyjaciel z Olkusza przesłał mi wspaniały lokalny przysmak.
My friend from Olkusz sent me a wonderful local delicacy.
In this instance, 'Olkuszu' highlights the use of the town's name in conversation topics.