In the Greek myth of Pandora’s Box, Zeus gives Pandora a sealed jar to carry before she reaches Epimetheus. In Hesiod’s original account, the object is a pithos, a large storage vessel rather than a small modern box.
The jar contains destructive troubles that have not previously afflicted humanity. Pandora opens it, and the contents escape into the world. Hesiod’s wording makes the vessel part of Zeus’s plan: Pandora is sent as an apparently desirable gift, while the concealed container carries the consequences of accepting it.
The familiar phrase “Pandora’s box” developed later because translators rendered the Greek vessel as a box or chest. The original object was more like a large earthenware storage jar. “Sealed jar” is therefore a clear description of the mythic object without repeating the specialized Greek term often tested in versions of this question.