This is the 175th most frequent Serbian word.
новембра
"Новембра" means "of November" in English.
In this sentence, 'новембра' is used as a genitive case of 'новембар' to indicate the specified date.
Данас је тридесети новембра.
Today is the thirtieth of November.
Here, 'новембра' serves in genitive case due to its relationship to the phrase specifying time.
Испити почињу крајем новембра.
Exams start at the end of November.
In this context, the preposition 'у' requires the locative case, therefore 'новембру' is used, not 'новембра'; this demonstrates the versatility in case usage of Serbian nouns depending on sentence context.