Middle Welsh erchi

← Proto-Brythonic *ėrxɨd (inherited)

← Proto-Brythonic *ėrxɨd (inherited(wlm/cy))

← Proto-Celtic *ɸarsketi (inherited)

← Proto-Celtic *ɸarsketi (inherited(wlm/cy))

← Proto-Indo-European *pr̥sḱéti (inherited)

← Proto-Indo-European *preḱ- (mention)

← Proto-Indo-European *pr̥sḱéti (inherited(wlm/cy))

→ Welsh erchi (inherited)

→ Middle Welsh arch (mention)