köken: Etymology tree Proto-Indo-European *sew-? Proto-Indo-European *sewH- Proto-Indo-European *suHnús Proto-Balto-Slavic *sū́ˀnus Proto-Slavic *sy̑nъ Old Polish syn Polish syn Proto-Indo-European *-kos Proto-Slavic *-kъ Proto-Slavic *-ъkъ Old Polish -ek Polish -ek Polish synek From syn + -ek.