Definition of "mod"

noun:
- A 1960s British person who dressed in unconventionally modern style and was interested in modernism and the modern music of the time; the opposite of a rocker.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- A modification to an object, computer game, etc., typically for the purpose of individualizing and/or enhancing the performance of the object.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
verb:
- To modify an object from its original condition, typically for the purposes of individualizing and/or enhancing the performance of the object.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License