A pithos is the Greek vessel that appears in Hesiod’s Pandora story, rather than a small box.
A pithos was a large storage jar used in the ancient Greek world for materials such as grain, oil, or wine. In Works and Days, Hesiod describes Pandora receiving a container from Zeus and opening it, allowing troubles to spread among humanity. The Greek word is commonly transliterated as pithos.
The modern phrase “Pandora’s box” developed later and does not precisely preserve the ancient object. Renaissance translation choices, especially in Latin, helped turn the jar into the box familiar in English and many other languages.
Other Greek vessel names are not interchangeable. An amphora is a two-handled jar, a krater is a mixing vessel, and a kylix is a drinking cup. The pithos is the specific container associated with Hesiod’s account.