Tholus

Part of speech: noun

Definitions

1. A low, rounded hill or dome-shaped mound, often found on the surface of a planet or moon such as Mars
2. A smooth, domed elevation rising from a plain, commonly observed in planetary geology as a rounded summit
3. A gently rounded mound or hillock, a term used in astronomy and geology for dome-like features on celestial bodies

Etymology: Latin "tholus" meant "dome" or "rotunda," a rounded structure rising above a building. Its Greek relative, "tholos," had the same general sense and was used for round buildings of various kinds, so the two words are doublets: one entered English through the classical Greek path, the other directly from Latin. In English, "tholus" is used for a low, rounded hill, the shape that a dome brings to mind when seen across open land. The word keeps the image of a curved roof while shifting its setting from architecture to landscape. A hill that bulges gently out of a plain looks like an upturned bowl, and geologists and astronomers apply the term to such features on other worlds as well, reusing the old architectural picture for natural landforms.

Synonyms: dome