Scottish Gaelic piuthar

← Proto-Celtic *swesūr (inherited)

← Proto-Indo-European *swésōr (inherited)

← Old Irish fiur (inherited)

← Old Irish phiur (mention)

← Old Irish siur (mention)

→ Scottish Gaelic leas-phiuthar (prefix)

→ Scottish Gaelic mac-peathar (affix)

→ Scottish Gaelic leth-phiuthar (prefix)