This is the 1868th most frequent Polish word.
kuba
The Polish word "kuba" is a proper noun used as a given name (Jacob/James) or refers to the country "Cuba".
In this sentence, 'Kuba' is used as a toponym, the Polish name for the country Cuba.
Odwiedziłem Kubę w zeszłym roku.
I visited Cuba last year.
Here, 'Kuba' is used as a vocative case to directly address someone named Kuba.
Kuba, przynieś proszę książkę ze stołu.
Kuba, please bring the book from the table.
Here, 'Kuba' is used as a proper noun, specifically a male given name.