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