This is the 5972nd most frequent Russian word.
сентябрь
"September" - the ninth month of the year.
The word 'сентябрь' is used in the grammatical form 'сентябре', which is the prepositional case, indicating the time 'in September'.
В сентябре начинается учебный год.
In September, the academic year begins.
The word 'сентябрь' is used in its nominative case to denote the subject of the sentence, referring to the month itself.
Сентябрь - это месяц яркой осени.
September is the month of bright autumn.
The word 'сентябрь' is used in the accusative case 'сентябрь', indicating the object towards which the feelings are directed.