In Hesiod’s Works and Days, a jar holds the world’s evils in Pandora’s story.
The original Greek word is pithos, a large storage jar commonly used for grain, wine, or oil. Hesiod does not describe a wooden box. The familiar “box” wording arose much later through a translation tradition, especially after the Renaissance.
According to the myth, Zeus gives Pandora a sealed jar and instructs her not to open it. Curiosity leads her to lift the lid, releasing sickness, labor, sorrow, and other troubles into the human world. One thing remains inside: hope.
The image of a box is now so firmly established that “Pandora’s box” is the standard expression in English. However, ancient Greek vase paintings and texts support the jar interpretation, making “a jar” the historically precise answer.