Where does “четврток” come from?
четврток (Macedonian) comes from Proto-Slavic četvьrtъkъ, from Proto-Slavic četvьrtъ, from Proto-Balto-Slavic ketwirtas, from Proto-Indo-European *kʷetwr̥tós.
четврток (Macedonian): Thursday
Ancestry of “четврток”, step by step