1. Something that has been scraped or rubbed off, such as skin: The nurse put medication on the abrasion of the child's knee.

The abrasion on Rodney's knee finally healed and the abrasion on Nancy's elbow has been healing very well.

2. Erosion caused by rubbing or scraping, as of rock by wind, water, etc.: Years of abrasions had worn the surface of the stones so they are now smooth.

The abrasions on the cliff side were examples of the destructive powers of natural resources, winds, and water.

3. Etymology: from Medieval Latin (about A.D. 700 to A.D. 1500) abrasionem, abrasio, "a scraping"; from Latin abradere, "to scrape away, to shave off"; from ab-, "off" + radere, "to scrape" or "to rub".

The erosion of the sea floor by the movement of wave-agitated sediment; wave erosion: In geology, tidal waves and rolling water in oceans cause marine abrasion, which wears or grinds down the deposits and residue on the bottom of ocean waters.