In Greek mythology, the original container later known as Pandora’s box was a jar.
The earliest surviving literary versions of the story use the Greek word pithos, a large storage jar commonly used for commodities such as grain, oil, or wine. It was not originally described as a small wooden box. The jar held destructive forces that escaped when Pandora opened it.
The “box” wording became established through a translation tradition. The Renaissance scholar Desiderius Erasmus translated pithos into Latin as pyxis, a word meaning box or small container, and the familiar English phrase developed from that change.
This translation detail explains why modern illustrations often show Pandora opening a hinged chest even though the ancient Greek story points to a jar. “Pandora’s jar” is historically more precise, but “Pandora’s box” remains the standard expression in English for a source of unexpected trouble.