noun (n)

• a substance that abrades or wears down(noun.substance)

  Synonym:
  abrasive, abrasive material
  

  source: wordnet30
• a tool or machine used for wearing down or smoothing or polishing(noun.artifact)

  Synonym:
  abrader
  

  source: wordnet30
• A material used for grinding, as emery, sand, powdered glass, etc.(noun)

  source: webster1913