Old Irish daig

← Proto-Celtic *degʷi- (inherited)

← Welsh goddaith (cognate)

← Proto-Indo-European *dʰegʷʰ- (root)

← Proto-Indo-European *dʰegʷʰ- (inherited)

→ Irish fiabhras (cognate)

→ Irish daigh (inherited)

→ Scottish Gaelic fiabhras (cognate)