In Hesiod’s Works and Days, Pandora opens a jar, not a box, in the earliest surviving Greek account. Hesiod uses the Greek word pithos, which refers to a large storage jar or container.
The familiar phrase “Pandora’s box” developed much later through a translation tradition. In the sixteenth century, the humanist Erasmus rendered pithos as the Latin pyxis, meaning a box or small container. That choice helped establish the form now common in English and many other languages.
The original vessel was not necessarily a small household jar. A pithos could be a large ceramic storage container used for commodities such as grain, oil, or wine. Its size and function make the later “box” image an adaptation rather than a literal description of Hesiod’s object.
This is one of the most persistent classical-literature mix-ups. The myth is ancient, but the box wording is a later interpretive development, while the earliest surviving Greek version specifically describes a jar.