Dune

A dune is a landform built up from wind driven or water driven sand, typically taking the shape of a mound, ridge, or hill. A single dune sits within a wider dune system, a large expanse of dune systems is called a dune field, and a broad flat area of wind swept sand with little vegetation is called an erg or sand sea. Most dunes are longer on their upwind, or stoss, side, where sand is pushed up the slope, and have a shorter slip face on the downwind, or lee, side, with the low trough between two dunes called a dune slack. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/