In Greek mythology, Pandora received a jar from Zeus that she was warned not to open.
The familiar English phrase “Pandora’s box” comes from a translation mistake. In Hesiod’s Greek account, the object is a large storage jar, called a pithos, rather than a box. Pandora opened it, releasing troubles into the world.
The story appears in Hesiod’s poems Works and Days and Theogony. Later European retellings and translations changed the container into a box, helping create the modern expression for an action that produces many unforeseen problems. The jar is therefore the most historically precise answer, while “box” is the conventional modern phrase.
The myth also includes hope, which remains associated with the jar after the other afflictions escape. Interpretations differ over whether hope stayed inside or was released later, but the container itself is identified as a jar in the ancient source.