It is the constantly wearing away that the earth’s surface suffers when it is attacked by wind, water, streams, groundwater, glaciers and oceans.
In the picture, we see how the hard rocks remain while the soft rocks have disappeared. The river water also causes erosion on the earth's surface.
2. The wind
The wind itself can not wear away the rocks, but when it transports solid particles of sand or dust in suspension, it produces continuous erosion. It will be stronger if the wind speed and the number and size of particles that it transports is greater.
In the picture, we see how the wind, sweeping along bits of sand and other bodies, erodes a rock that has the form of a mushroom.