This is the 127th most frequent German word.
oktober
"October" (the tenth month of the year).
Here, 'Oktober' is a noun representing the month October, describing a time period in the sentence.
Im Oktober beginnen die Blätter zu fallen.
In October, the leaves begin to fall.
'Oktober' is functioning as the subject of the sentence, referring to the month specifically.
Der Oktober ist einer der buntesten Monate des Jahres.
October is one of the most colorful months of the year.
Here, 'Oktober' is used to specify the time frame for an event, which is occurring in the month.