Erosion
- The wearing away of land surface by wind or water. Erosion occurs naturally from weather or runoff but is often intensified by peoples practices. [source: http://www.ks.nrcs.usda.gov]
- The gradual wearing away of rock or soil by physical breakdown, chemical solution, and transportation of material, as caused, e.g. by water, wind, or ice [source: http://encarta.msn.com]
