Where does “opis-” come from?

opis- (English) comes from Ancient Greek ὄπισθεν, from Ancient Greek -θεν, from Proto-Indo-European *-dʰe — locative suffix.

Ancestry of “opis-”, step by step

StepLanguageWordMeaning
1Ancient Greekὄπισθενbehind, at the back; backwards; in the future,...
2Ancient Greek-θενfrom; also used, like genitive, with prepositions
3Proto-Indo-European*-dʰelocative suffix
Every word from Proto-Indo-European *-dʰe →Every word from Ancient Greek -θεν →Every word from Ancient Greek ὄπισθεν →