In planetary nomenclature, a chasma /ˈkæzmə/ (plural: chasmata /ˈkæzmətə/) is a deep, elongated, steep-sided depression.[1] As of 2020, the IAU has named 122 such features in the Solar System, on Venus (63), Mars (25), Saturn's satellites Mimas (6), Tethys (2), Dione (8) and Rhea (5), Uranus's satellites Ariel (7), Titania (2) and Oberon (1) and Pluto's satellite Charon (3). An example is Eos Chasma on Mars.