Where does “プロイセン” come from?

プロイセン (Japanese) comes from German Preußen, from Middle High German Prūzin.

Ancestry of “プロイセン”, step by step

プロイセン traces back through two separate lines of ancestry.

via German Preußen

StepLanguageWordMeaning
1GermanPreußen—
2Middle High GermanPrūzin—

via Dutch Pruisen

StepLanguageWordMeaning
1DutchPruisen—
Every word from Middle High German Prūzin →Every word from German Preußen →