noun

• (informal) A demonstration or visual explanation.
  "The professor prepared a demo to help her class understand the topic."
• (informal) A recording of a song meant to demonstrate its overall sound for the purpose of getting it published or recorded more fully.
  "After hearing the demo the record label approved funding to record the song with a full band."
• (informal) An example of a product used for demonstration and then sold at a discount.
• (informal) A march or gathering to make a political protest.
  "Elli standing there, takes a sip of her tea, fixes hostile eyes on Somraj and says, ‘Well, what are you waiting for? You signed the petition against yourself, will you now join our demo against you?’"

adj

• (of a commercial product) designed to test consumers' interest in a retail item prior to purchasing.
  "This Nutty Kid leavin' 'Crazy Face Selfies' On Demo Products..."

verb

• (informal) To record a demo version of a song, usually not intended for commercial release.
  "The band demoed thirty songs. Their manager thought that ten of the songs would make a good record."
• (informal) To demonstrate.

verb

• (informal) To demolish (especially a house or fixture).
  "This means we are going to demo the house to the dirt, or hopefully leave one wall standing."