Old Irish íarn

← Breton houarn (cognate)

← Proto-Celtic *īsarnom (inherited)

← Welsh haearn (cognate)

← Proto-Indo-European *h₁ésh₂r̥ (derived)

→ Breton houarn (cognate)

→ Irish iarann (inherited)

→ Irish iarnaí (mention)

→ Scottish Gaelic iarann (inherited)

→ Manx yiarn (inherited)