In Greek mythology, Pandora opened a jar before the story became known as Pandora’s box.
Hesiod’s Works and Days describes a large storage vessel, commonly identified with the ancient Greek word pithos. A pithos was a substantial ceramic container used for storing commodities such as grain, oil, or wine. Its size and practical role were very different from the small hinged box usually shown in modern illustrations.
The “box” wording developed through translation history. The Renaissance humanist Erasmus translated the relevant Greek term into Latin as pyxis, meaning a box or small container. That choice helped establish the expression “Pandora’s box” in European languages, even though Hesiod’s original image was a jar.
The container is not always described identically in later retellings. Artists, poets, and popular storytellers have adapted its shape, lid, and material. Nevertheless, the ancient literary source and the standard classical interpretation point to a jar, making “box” a later conventional label rather than the original object.