1911 Encyclopædia Britannica/Abrasion

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ABRASION (from Lat. ab, off, and radere, to scrape), the process of rubbing off or wearing down, as of rock by moving ice, or of coins by wear and tear; also used of the results of such a process as an abrasion or excoriation of the skin. In machinery, abrasion between moving surfaces has to be prevented as much as possible by the use of suitable materials, good fitting and lubrication. Engineers and other craftsmen make extensive use of abrasion, effected by the aid of such abrasives as emery and carborundum, in shaping, finishing and polishing their work.