For our purposes in talking about framing stories, we will define the story being framed as the plotlines explored directly by the narrative. To take a well-known example, look at Harry Potter. The plotlines of the character arcs, and combatting Voldemort, are the core story. A framing story could be if there were a line at the beginning or end of the books saying "based upon the diaries of Harry Potter, Wizard." Which takes us conveniently to the next set of definitions we need to supply.
No, I'm not above using cliche titles, when they serve me. Because I'm so very fond of stirring up controversy, I'm going to talk about something that divides more people than religion, politics, or the Great Pumpkin: movie/book adaptations. Fair warning: we're going to talk about some big name franchises, including Harry Potter, Star Wars, The Lord of the Rings, Star Trek, Jurassic Park, and others, so if you don't want to risk potential spoilers from either the book or movie versions of any of these, you might not want to read this post. Otherwise, let's mire ourselves in controversy.
If you've been a follower of the site for awhile, you may remember the post "Written in a Corner." In that post, I mentioned that I would write another post addressing the topic of plausible impossibility, which is an important concept in speculative fiction writing. Of course, if you've been a follower of the site for awhile, you probably also have realized that I'm not always very good at following up on these post ideas that I drop in my posts in anything approaching a timely fashion. Don't worry, I'll get to it eventually. In this case, it's only taken me a couple months.
As I'm working on the Fo'Fonas series, I've made the decision that I'm going to write rough drafts of every novel in the series before I will seek to publish even the first one. I think this will improve the strength of all of the novels, since I'll be able to better tie everything together and generally make for a tighter story. It will also make my job as a writer easier, because I won't be stuck with an immutable origin when I get to later parts of the series.