In Greek mythology, Pandora’s container was a pithos in the original Greek tradition. A pithos was a large storage jar used in the ancient Greek world for commodities such as grain, oil, or wine.
Hesiod’s Works and Days describes Pandora opening this kind of vessel, from which evils escape into the world. The familiar phrase “Pandora’s box” became standard because of a translation tradition associated with Erasmus, who rendered the Greek vessel as a box or container in Latin-influenced retellings.
The difference explains why ancient vase paintings and modern illustrations can look so unlike one another. A pithos was generally a substantial jar, not a small hinged box with a lid. The modern box image is now firmly established in English culture, even though it is not the most literal representation of Hesiod’s object.
“Pithos” is more specific than simply saying “jar.” Krater, lekythos, and amphora are other Greek vessel types, but they are not the container named in the Pandora story.