This is a list of named geological features on Saturn's moon Titan. Official names for these features have only been announced since the 2000s, as Titan's surface was virtually unknown before the arrival of the Cassini–Huygens probe. Some features were known by informal nicknames beforehand; these names are noted where appropriate. Note that some features with a physical size given by "diameter" may not be circular; then the number refers to the length. Albedo features Albedo features on Titan are named after sacred or enchanted places in world mythologies and literature. Bright albedo features Dark albedo features Arcūs Titanean arcūs (arc-shaped features) are named after deities of happiness. Colles Colles are small hills or knobs which are named after characters in J. R. R. Tolkien's Middle-earth. Craters Craters on Titan are named after deities of wisdom. Faculae Faculae (bright spots) are named after islands on Earth that are not politically independent. Groups of faculae are named after archipelagos on Earth. Fluctūs The term "fluctus" refers to flow terrain. Fluctūs on Titan are named after mythological figures associated with beauty. Flumina A flumen is a feature that looks like a channel carved by liquid. Flumina refers to a network of rivers. Some flumina are not found near liquid bodies, which are labelled as "dry valley". They are named after mythical or imaginary rivers. Freta A fretum (plural freta) is a strait of liquid connecting two larger liquid bodies. They are named after characters from the Foundation series of science fiction novels by Isaac Asimov. Insulae Insulae are islands within Titan's seas. They are named after legendary islands. Labyrinthi Labyrinthi (complexes of intersecting valleys or ridges) on Titan are named after planets from the fictional Dune universe created by Frank Herbert. Lacunae Lacunae are dark areas with the appearance of dry lake beds, which are named after intermittent lakes on Earth. Lacūs Lacūs (plural form of lacus used in Titan geological nomenclature) are hydrocarbon lakes. Large ringed features Large ring features are named after deities of wisdom in world mythology. Maculae Titanean maculae (dark spots) are named after deities of happiness, peace, and harmony in world mythology. Maria Maria (plural of mare) are hydrocarbon seas. Montes Mountains are named after mountains from the fictional Middle-Earth created by J.R.R. Tolkien. Paterae Paterae are caldera or deep-wall craters with a possible volcanic origin. Sotra Patera was formerly named Sotra Facula, which followed the naming