In Greek mythology, Hesiod originally described Pandora opening a jar. The Greek word is pithos, a large storage vessel commonly used for commodities such as grain, wine, or oil.
The expression “Pandora’s box” became standard much later because of a translation history. The sixteenth-century humanist Erasmus rendered the Greek container with the Latin word pyxis, meaning a box or small container, rather than preserving the image of a large jar.
That change shaped European art and language. Today, “opening Pandora’s box” means starting a process that releases many unexpected problems, even though the earliest written version does not contain a box.
The jar itself is important to the ancient setting: a pithos was a practical household or agricultural vessel, not a magical jewel box. Modern illustrations often show a small ornate box because that image fits the later idiom better than Hesiod’s original container.