"Mom, Dad, Teacher; what does (fill in the word here) mean?" "Go look it up in the dictionary," is what they may reply whether or not they know the meaning of the word. That normally solves what the meaning of the word is. Unless of course the word has multiple meanings Then, things start to get a little bit complicated.
I believe that a dictionary is a type of non-fiction book. Do not worry; I do not spend all of my time reading them. I do not want anyone out there to get worried that all I am reading is the dictionary. Getting back on topic, dictionaries are different types of non-fiction books . The reason is that they remind us that words as well as situations in life can have many meanings and interpretations. For example, the word dog can mean a wonderful, furry companion; or it can mean a scumbag of a guy. The word book can be used as a noun to describe a great item with paper that you can read. Other times, it is a verb describing what you do to purchase an airline flight.
Sometimes, non-fiction changes over time. For example, we sometimes find out more about history than we knew before As a result, the non-fictions books about it have to change. Meanings of words change too as a result of history, social change, or other societal factors. The word gay used to mean extremely happy. It is now primarily used to describe someone who wishes to have a romantic relationship with the same sex. In addition, the meanings of words can become clearer overtime. The word sofa used to mean davenport. What the heck is a davenport? Sofa is now often interchangable with the word couch.
I guess the point I am trying to make is that dictionaries are non-fiction, but they continue to change and grow in their knowledge overtime. They have to...they are non-fiction which represents real life. . Maybe some night at 2:00am when you are looking up a word for a college term paper, a work project, or just because you need/want to, you may think about it this way. If you do not, that is okay. Dictionaries are still non-fiction that needs to change just the same. There are also always people who need them to change. Interesting food for thought.