The category is exceptionally broad.  A Professor from Florida who analyzed the categorizations of the data gives an example from personal experience: he was concerned for his daughter's safety, so he drove to her home.  There was no problem -- she was simply out walking her dog.  He forgot to bring his handgun, but had intended to.  The fact that he intended to was recorded in some surveys as defensive gun use.  

80,000 means an average of 219 per day.   Let's see your source for that -- I am somewhat familiar with Hemenway's research and swear on my mother's grave that your number is pure, pure fiction.  However, he did write a paper about extreme overestimates; perhaps the ridiculous "80,000" number is one of those.  The paper is called Survey Research and Self-Defense Gun Use: An Explanation of Extreme Overestimates."  It's online, so start reading.