Where does “pikkukoskelo” come from?

pikkukoskelo (Finnish) comes from Finnish pikku, from Finnish pieni, from Proto-Finnic peeni — little, small; fine.

Ancestry of “pikkukoskelo”, step by step

pikkukoskelo traces back through two separate lines of ancestry.

via Finnish pikku

StepLanguageWordMeaning
1Finnishpikkulittle, small; little old
2Finnishpienilittle, small; Third-person singular indicative...
3Proto-Finnicpeenilittle, small; fine

via Finnish koskelo

StepLanguageWordMeaning
1Finnishkoskeloa merganser
2Proto-Finno-Ugric*kośka
Every word from Proto-Finnic peeni