Where does “toisiapäin” come from?

toisiapäin (Finnish) comes from Finnish toinen, from Proto-Finnic toinen, from Proto-Finnic too, from Proto-Uralic to — that.

Ancestry of “toisiapäin”, step by step

toisiapäin traces back through two separate lines of ancestry.

via Finnish toinen

StepLanguageWordMeaning
1Finnishtoinensecond; other, another; the others, other ones
2Proto-Finnictoinensecond; other
3Proto-Finnictoothat over there, yonder distal?
4Proto-Uralictothat

via Finnish päin

StepLanguageWordMeaning
1Finnishpäinagainst, to, on etc; Used to indicate approximate...
2Finnishpäähead; end, tip
3Proto-Finnicpäähead
4Proto-Uralicpäŋehead
Every word from Proto-Uralic toEvery word from Proto-Finnic tooEvery word from Proto-Finnic toinen
toisiapäin — Etymology, Origin & Word History | Etymology Explorer