Definition of "demo"

noun:
- A brief demonstration or visual explanation.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- A recording of a song meant to demonstrate its overall sound for the purpose of getting it published or recorded more fully.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- An example of a product used for demonstration and then sold at a discount.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- A march or gathering to make a political protest.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
- An edition of limited functionality to give the user an example of how the program works.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License
verb:
- To record a demo version of a song, usually not intended for commercial release.
  
  from Wiktionary, Creative Commons Attribution/Share-Alike License