Definition of "grate"

noun:
- A horizontal metal grille through which water, ash, or small objects can fall, while larger objects cannot.
  
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verb:
- To shred things, usually foodstuffs, by rubbing across a grater.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- To rub against, making a (usually unpleasant) squeaking sound.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- To grate on one's nerves; to irritate or annoy.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License