Every word or phrase you don't understand if a reference to something you don't know.
@zatnosk all books and text are remixes of the dictionary
@zatnosk remixes of the alphabet then :3
@Nine 
now I'm considering how many books have used invented symbols in the text, and not just described them or used them in illustration and decoration.
Hmm.
@Nine not fantasy and scifi books, there's plenty of words in those that doesn't exist anywhere else :D