Proto-Slavic *četvьrtъkъ

→ Belarusian чацвер (inherited)

→ Czech čtvrtek (inherited)

→ Kashubian czwôrtk (inherited)

→ Kashubian czwiôrtk (inherited)

→ Lower Sorbian stwórtk (inherited)

→ Upper Sorbian štwórtk (inherited)

→ Hungarian csütörtök (derived)

→ Macedonian четврток (inherited)

→ Polish czwartek (inherited)

→ Russian четверг (inherited)

→ Yakut чэппиэр (derived)

→ Slovak štvrtok (inherited)

→ Slovene četrtek (inherited)

→ Silesian sztwortek (inherited)

→ Silesian sztwŏrtek (inherited)

→ Ukrainian четвер (inherited)