This is the 1234th most frequent Polish word.
sosnowcu
"Sosnowcu" is the locative form of "Sosnowiec," a city in Poland.
Here, 'Sosnowcu' is the locative case form of 'Sosnowiec', used to indicate location.
W Sosnowcu znajduje się piękny park.
In Sosnowiec, there is a beautiful park.
In this sentence, 'Sosnowcu' again appears in the locative case, demonstrating its use to specify the city in which an event occurred.
Byłem ostatnio w Sosnowcu na koncert.
I was recently in Sosnowiec for a concert.
'Sosnowcu' is used in the locative case in this sentence to indicate the place where the basilica is located.