In Hesiod’s Pandora myth, the container later translated as a box was a pithos. A pithos was a large ancient Greek storage jar, commonly used for commodities such as grain, oil, or wine.
Hesiod’s Greek wording describes Pandora receiving a pithos, not a small hinged chest. The familiar image of a “box” became dominant after later translation and retelling, especially in Renaissance Europe.
The distinction matters because a pithos could be a substantial earthenware vessel. It fits the practical storage containers known from the ancient Greek world far better than the modern decorative box usually shown in illustrations.
“Pandora’s jar” is consequently a historically closer translation than “Pandora’s box,” although the latter is now the standard English expression and the source of the idiom.