Where does “Ylisaukko-oja” come from?

Ylisaukko-oja (Finnish) comes from Finnish oja, from Proto-Slavic oje, from Proto-Indo-European h₂oyHsos.

Ancestry of “Ylisaukko-oja”, step by step

Ylisaukko-oja traces back through two separate lines of ancestry.

via Finnish oja

StepLanguageWordMeaning
1Finnishojaditch, trench; small natural brook
2Proto-Slavicojethill, shaft
3Proto-Indo-Europeanh₂oyHsos—

via Finnish saukko

StepLanguageWordMeaning
1FinnishsaukkoEuropean otter, "Lutra lutra"; otter; Old World...
2Proto-Finnicsagukkoi—
3Proto-Finnicsagarvaotter
Every word from Proto-Indo-European h₂oyHsos →Every word from Proto-Slavic oje →Every word from Finnish oja →