Where does “-o” come from?

-o (Esperanto) comes from Spanish -ó, from Latin Aramaicus, from Ancient Greek Ἀραμαϊκός, from Aramaic ܐܪܡܝܐ, from Aramaic ארמיא, from Aramaic ארם — Aram (son of Shem).

-o (Esperanto): Nominal suffix. Most Esperanto nouns end in "-o";...