Cornish er

← Breton erer (cognate)

← Proto-Celtic *eriros (inherited)

← Welsh eryr (cognate)

← Proto-Indo-European *h₃érō (derived)

← Old Irish *irar (cognate)

→ Breton erer (cognate)

→ Welsh eryr (cognate)

→ Cornish Sowsneger (suffix)

→ Cornish kiger (suffix)

→ Cornish Godhaleger (suffix)