abrasion

abrasion (http://definr.com/abrasion)

     n 1: an abraded area where the skin is torn or worn off [syn: scratch,
           scrape, excoriation]
     2: erosion by friction [syn: attrition, corrasion, detrition]
     3: the wearing down of rock particles by friction due to water
        or wind or ice [syn: grinding, attrition, detrition]