Erosion is a broadly defined group of processes involving the movement of soil and rock. This movement is often the result of flowing agents, whether wind, water, or ice, which sometimes behaves like a fluid in the large mass of a glacier. Gravitational pull may also influence erosion. Thus, erosion, as a concept in the earth sciences, overlaps with mass wasting or mass movement, the transfer of earth material down slopes as a result of gravitational force. Even more closely related to erosion is weathering, the breakdown of rocks and minerals at or near the surface of Earth owing to physical, chemical, or biological processes. Some definitions of erosion even include weathering as an erosive process.

This is an old dune that has, due to erosion of the dunes infront of it, become exposed to the sea (Fig- 1). The front of the dune shows a debris pile consisting of sand that has fallen from the face during the last couple of days. The sea now reaches this dune at the highest tides and erosion will be rapid. Note how the root systems of the grasses are exposed along the top of the dune, showing how they penetrate the sand and bind it together.