Old Church Slavonic дъно

← Proto-Balto-Slavic *dúbna (inherited)

← Proto-Indo-European *dʰewbʰ- (root)

← Proto-Indo-European *dʰubʰnós (derived)

← Proto-Slavic *dъno (inherited)

→ Old Church Slavonic бездъна (affix)

→ Ancient Greek βυθός (cognate)

→ Lithuanian dugnas (cognate)

→ Old Prussian dubnas (cognate)

→ Romanian Bâzdâna (affix)