A crescent-shaped dune whose tips point downwind.

A crescent-shaped dune that forms around a small patch of vegetation, lies perpendicular to the prevailing wind direction, and has a gentle, convex windward slope and a steep, concave leeward slope. Barchan dunes typically form in arid, inland deserts with stable wind direction and relatively little sand.

an arc-shaped sand ridge, comprised of well-sorted sand