Old Irish uinnius

← Breton onn (cognate)

← Proto-Celtic *osnistū (inherited)

← Proto-Celtic *osnos (derived)

← Welsh onn (cognate)

← Proto-Indo-European *h₃esnos (derived)

← Latin ornus (cognate)

← Russian я́сень (cognate)

→ Welsh onn (cognate)

→ Irish fuinseog (mention)

→ Scottish Gaelic uinnseann (mention)

→ Middle Irish fuinnseóg (mention)