Where does “сентябр” come from?

сентябр (Tajik) comes from Russian сентя́брь, from Latin september, from Latin Septem, from Proto-Italic septem, from Proto-Indo-European septḿ̥ — seven.

сентябр (Tajik): September

Definitions

September

Ancestry of “сентябр”, step by step

Step	Language	Word	Meaning
1	Russian	сентя́брь	—
2	Latin	september	of September
3	Latin	Septem	—
4	Proto-Italic	septem	seven
5	Proto-Indo-European	septḿ̥	seven

Every word from Proto-Indo-European septḿ̥ →

сентябр — Etymology, Origin & Word History | Etymology Explorer