Welsh bôn

← Proto-Celtic *bonus (inherited)

← Old Irish bun (cognate)

← Middle Welsh bon (inherited)

→ Welsh gwrthban (affix)

→ Welsh danfon (mention)

→ Welsh bontin (affix)

→ Welsh safon (compound)

→ Welsh boncyff (compound)

→ Welsh bongorff (compound)

→ Irish bun (cognate)

→ Scottish Gaelic bun (cognate)

→ Old Irish bun (cognate)