Burr or Burrr or Brrr is a sound that is being used to describe a general state of confusion or otherwise is used to fill any akward pauses in conversation. The sound's usage is currently increasing exponentially in the US office scene. Origins of the sound are still debatable although it has been rumored to have been created in New York. Also can have comedic uses.
While sitting in your boss's office, you're told to do something you don't undertand. You look back at your boss while tilting your head at appoximately 37 degrees and reply..."Brrrr?"