This is the 8253rd most frequent Polish word.
ołeksandr
"Ołeksandr" is a Polish transliteration of the Ukrainian name "Олександр," equivalent to "Alexander" in English.
Here, 'Ołeksandr' is used as a proper noun, referring to the name of a person.
Ołeksandr jest moim najlepszym przyjacielem.
Ołeksandr is my best friend.
In this sentence, 'Ołeksandr' is used in the instrumental case (Ołeksandrem), showing the person with whom the action occurred.
Wczoraj rozmawiałem z Ołeksandrem o książkach.
Yesterday, I spoke with Ołeksandr about books.
Here, 'Ołeksandr' is used in the genitive case (Ołeksandra), indicating possession.