Welsh wy

← Proto-Celtic *āwyom (inherited)

← Proto-Indo-European *h₂ōwyóm (inherited)

← Old Welsh ui (inherited)

← Middle Welsh wy (inherited)

→ Breton vi (cognate)

→ Welsh w (link)

→ Welsh wyau (affix)

→ Welsh wy maes (compound)

→ Cornish oy (cognate)