köken: PIE word *septḿ̥ Inherited from Old East Slavic сентѧбрь (sentębrĭ), семтѧбрь (semtębrĭ), септѧбрь (septębrĭ), септѧбръ (septębrŭ), септѧмбрь (septęmbrĭ), via Old Church Slavonic септѧбр҄ь (septębrʹĭ), from Byzantine Greek Σεπτέμβριος (Septémbrios) from Latin september (“seventh month”), from septem (“seven”). See also седьмо́й (sedʹmój), Ukrainian ве́ресень (véresenʹ, “September”), Old East…