What is a 10 book series called?
Excuse me, could you please clarify what you mean by a "10 book series"? Are you referring to a collection of ten books that are interconnected in some way, perhaps through a shared universe, characters, or plotline? If so, the term for such a collection is simply a "ten-book series." However, without more specific information about the series itself, such as its title or author, it's difficult to provide a more detailed description. Could you please elaborate on what you're asking?