沙丘 (shā qiū) literally means 'sand hill' — 沙 (shā) means 'sand', and 丘 (qiū) means 'hill' or 'mound'. Together, they refer to a natural landform created by wind-blown sand accumulating into a ridge or dune, commonly found in deserts or along coastlines. Unlike artificial mounds, sand dunes are dynamic: their shape and position can shift over time due to wind patterns and vegetation cover.

This term is used in geography, environmental science, and travel contexts — for example, when describing landscapes in northwestern China like the Taklamakan or Badain Jaran Deserts. It’s a neutral, formal noun; you’ll rarely hear it in casual daily conversation unless discussing travel, nature, or weather phenomena. While 丘 alone can mean 'hill' in literary or place names (e.g., 珠穆朗玛峰北丘), 沙丘 specifically evokes arid, open terrain shaped by wind erosion and deposition.