In the film Avatar, Pandora is a moon.
James Cameron’s Avatar is set largely on Pandora, a fictional habitable moon orbiting the gas giant Polyphemus in the Alpha Centauri star system. The moon is home to the Na’vi and contains the valuable mineral unobtanium, which drives the human mining operation central to the story.
Calling Pandora a moon rather than a planet is a specific world-building detail. It gives the setting a different astronomical context from Earth and allows the film to feature spectacular views of Polyphemus in Pandora’s sky. The story’s environment includes dense forests, unusual animals, floating mountains, and a complex biological network.
The film’s Pandora is unrelated to the ancient Greek woman except for the shared name. Cameron chose a mythologically resonant name for a world associated with discovery, danger, and consequences, but the movie does not retell the Greek myth.