This is the 478th most frequent Azerbaijani word.
sentyabrın
"Sentyabrın" means "of September" in English.
In this sentence, "sentyabrın" is the possessive form of "sentyabr" used to indicate 'at the end of September'.
Sentyabrın sonunda dərslər başlayır.
Classes start at the end of September.
Here, "sentyabrın" indicates a specific date within the month of September.
Biz sentyabrın birində evləndik.
We got married on the first of September.
In this context, "sentyabrın" is used to describe a time within September, particularly the middle.