Where does “purso-” come from?

purso- (Finnish) comes from Finnish pursua, from Proto-Finnic pursudak — to gush.

Ancestry of “purso-”, step by step

StepLanguageWordMeaning
1FinnishpursuaAlternative form of pursuta; to gush
2Proto-Finnicpursudakto gush
Every word from Proto-Finnic pursudak →Every word from Finnish pursua →