This is the 519th most frequent Russian word.
декабре
"Декабре" is the prepositional case of "декабрь," meaning "December" in English.
Here, "декабре" serves as the prepositional case to specify the time frame during which something happens.
В декабре дни становятся короче.
In December, the days become shorter.
"Декабре" operates as part of a prepositional phrase, 'в декабре,' describing when the holidays occur.
Праздники в декабре создают праздничное настроение.
The holidays in December create a festive mood.
The word "декабре" is used as a prepositional case form of "December" to indicate a point in time.