Proto-Indo-European *gʷowkólos

→ English boukólos rule (derived)

→ Breton bugel (inherited)

→ Welsh bugail (inherited)

→ Irish buachaill (derived)

→ Scottish Gaelic buachaill (derived)

→ Ancient Greek βουκόλος (inherited)

→ Ancient Greek βουκόλος (cognate)

→ Manx bochilley (inherited)

→ Old Irish búachaill (inherited)