The meaning of Erosion
Erosion is the washing away of the top layer of the surface of the earth by water or wind. Erosion can be caused by natural elements such as wind and glacial ice. The key to erosion is something called "fluid flow." Water, air, and even ice are fluids because they tend to flow from one place to another due to the force of gravity. Of the three, liquid water is the most common agent of erosion because there's so much of it on the surface of the Earth.