Gazetteer of Planetary Nomenclature
International Astronomical Union (IAU) Working Group for Planetary System Nomenclature (WGPSN)
Planetary Names: Feature Types

Descriptor Terms (Feature Types)

Descriptor terms are intended to represent morphological characteristics, not geological origin. The WGPSN does not endorse any specific scientific hypotheses when assigning descriptors.


Chart of landform types created in 1979 by Anne Gifford, who was then at the Air and Space Museum, Smithsonian Institution, Washington, D.C.


Feature (Designation) Description
Albedo Feature (AL) Geographic area distinguished by amount of reflected light
Arcus, arcūs (AR) Arc-shaped feature
Astrum, astra (AS) Radial-patterned features on Venus
Catena, catenae (CA) Chain of craters
Cavus, cavi (CB) Hollows, irregular steep-sided depressions usually in arrays or clusters
Chaos, chaoses (CH) Distinctive area of broken terrain
Chasma, chasmata (CM) A deep, elongated, steep-sided depression
Collis, colles (CO) Small hills or knobs
Corona, coronae (CR) Ovoid-shaped feature
Crater, craters (AA) A circular depression
Dorsum, dorsa (DO) Ridge
Eruptive center (ER) Active volcanic centers on Io
Facula, faculae (FA) Bright spot
Farrum, farra (FR) Pancake-like structure, or a row of such structures
Flexus, flexūs (FE) A very low curvilinear ridge with a scalloped pattern
Fluctus, fluctūs (FL) Flow terrain
Flumen, flumina (FM) Channel on Titan that might carry liquid
Fossa, fossae (FO) Long, narrow depression
Insula, insulae (IN) Island (islands), an isolated land area (or group of such areas) surrounded by, or nearly surrounded by, a liquid area (sea or lake).
Labes, labēs (LA) Landslide
Labyrinthus, labyrinthi (LB) Complex of intersecting valleys or ridges.
Lacuna, lacunae (LU) Irregularly shaped depression on Titan having the appearance of a dry lake bed
Lacus, lacūs (LC) "Lake" or small plain; on Titan, a "lake" or small, dark plain with discrete, sharp boundaries
Landing site name (LF) Lunar features at or near Apollo landing sites
Large ringed feature (LG) Cryptic ringed features
Lenticula, lenticulae (LE) Small dark spots on Europa
Linea, lineae (LI) A dark or bright elongate marking, may be curved or straight
Lingula, lingulae (LN) Extension of plateau having rounded lobate or tongue-like boundaries
Macula, maculae (MA) Dark spot, may be irregular
Mare, maria (ME) "Sea"; large circular plain; on Titan, large expanses of dark materials thought to be liquid hydrocarbons
Mensa, mensae (MN) A flat-topped prominence with cliff-like edges
Mons, montes (MO) Mountain
Oceanus, oceani (OC) A very large dark area on the moon
Palus, paludes (PA) "Swamp"; small plain
Patera, paterae (PE) An irregular crater, or a complex one with scalloped edges
Planitia, planitiae (PL) Low plain
Planum, plana (PM) Plateau or high plain
Plume, plumes (PU) Cryo-volcanic features on Triton
Promontorium, promontoria (PR) "Cape"; headland promontoria
Regio, regiones (RE) A large area marked by reflectivity or color distinctions from adjacent areas, or a broad geographic region
Reticulum, reticula (RT) reticular (netlike) pattern on Venus
Rima, rimae (RI) Fissure
Rupes, rupēs (RU) Scarp
Satellite Feature (SF) A feature that shares the name of an associated feature. For example, on the Moon the craters referred to as "Lettered Craters" are classified in the gazetteer as "Satellite Features."
Scopulus, scopuli (SC) Lobate or irregular scarp
Serpens, serpentes (SE) Sinuous feature with segments of positive and negative relief along its length
Sinus, sinūs (SI) "Bay"; small plain
Sulcus, sulci (SU) Subparallel furrows and ridges
Terra, terrae (TA) Extensive land mass
Tessera, tesserae (TE) Tile-like, polygonal terrain
Tholus, tholi (TH) Small domical mountain or hill
Unda, undae (UN) Dunes
Vallis, valles (VA) Valley
Vastitas, vastitates (VS) Extensive plain
Virga, virgae (VI) A streak or stripe of color