Inplanetary nomenclature, atholus/ˈθoʊləs/ (pl.tholi/ˈθoʊlaɪ/) is a smalldomical mountain or hill.[1][2] The word is from the Greek θόλος,tholos (pl.tholoi),[3] which means a circular building with a conical or vaulted roof.[4] The Romanstransliterated the word into the Latintholus, which meanscupola or dome.[5] In 1973, theInternational Astronomical Union (IAU) adoptedtholus as one of a number of official descriptor terms for topographic features onMars and other planets and satellites.[6][7] One justification for using neutral Latin or Greek descriptors was that it allowed features to be named and described before theirgeology orgeomorphology could be determined.[8] For example, many tholi appear to be volcanic in origin, but the term does not imply a specific geologic origin.[9] Currently (March 2015), the IAU recognizes 56 descriptor terms.[1] (SeePlanetary nomenclature.) Tholi are present onVenus,Mars, asteroid4 Vesta,dwarf planet Ceres, and onJupiter's moonIo.
