sentences:  "undae") is a Latin term meaning water, particularly water in motion as waves.The International Astronomical Union (IAU) adopted the term to describe "undulatory," dune-like features on other planets.Olympia Undae contains a variety of dune forms and wind-related (aeolian) depositional features, including sand sheets, transverse dunes, simple barchan dunes, mega-barchans, and complex barchanoid ridges.