Hesiod described Pandora opening a pithos, a large Greek storage jar, rather than a box. In Works and Days, the container holds the troubles that escape into the human world when Pandora opens it.
The word pithos refers to a substantial earthenware vessel used in ancient Greece for storing commodities such as grain, oil, or wine. It could be large and heavy, often standing on a base or partly sunk into the ground. That practical vessel is very different from the small hinged box commonly shown in modern art.
The familiar phrase “Pandora’s box” became widespread through later translation and literary tradition. The Latin word pyxis, meaning a small box or container, helped move the image away from Hesiod’s pithos. The change is therefore a history of transmission, not a detail found in the earliest Greek wording.
Recognizing the pithos helps separate the original myth from its later popular form. “Pandora’s jar” is more faithful to Hesiod, while “Pandora’s box” remains the standard modern expression.