Definition of erosion

gradual wearing away of land through processes of nature, as by streams and wind. The term is also used to indicate a gradual decline in such general business phrases as sales erosion and marketshare erosion.

the gradual wearing away of land through processes of nature, as by streams and winds.

Examples:

1. Deep gullies cut into unvegetated earth, caused by rainwater erosion
2. The Grand Canyon formed by erosion from the Colorado River
3. The Sphinx in Egypt, disfigured by wind erosion