Where does “ポンペイ” come from?

ポンペイ (Japanese) comes from Pohnpeian Pohnpei, from Pohnpeian pohn — upon.

Ancestry of “ポンペイ”, step by step

StepLanguageWordMeaning
1PohnpeianPohnpei—
2Pohnpeianpohnupon
Every word from Pohnpeian pohn →Every word from Pohnpeian Pohnpei →
ポンペイ — Etymology, Origin & Word History | Etymology Explorer