But what about other definitions?
The scope of Harry Potter certainly fits with the world in peril epic definition. But if you think about it, the majority of the seven books take place in a relatively small setting: Hogwarts. Part of the reason we never lose sight of the grand scale of the story is because the characters remain aware of the outside world; Hogwarts doesn't become a vacuum like school settings can be. But I think the other part of what makes this story epic is the details. The world is so real because Rowling imagined every single aspect of it. Hogwarts is rich with history--she came up with so much periphery information and inserted it so masterfully, I have a hard time thinking of a setting I imagined better than Hogwarts while I was reading. I actually had a hard time watching the first movie for the first time because my own internal images of Hogwarts were so distinct.
Stories that span more than one generation--or more than one century--in my mind qualify as epic, even if those generations or stories don't have a large impact on the world around them. The story Cloud Atlas comes to mind. I've only seen the movie, though I want to read the book, but it's the combination of all the characters and all their lives that make the story epic, more so than any one character or story thread could be on its own. Stories that span generations show how actions affect time, sometimes long after the action itself has finished and seems done by the people immediately related to it.
I'm not talking about epic heroes like Achilles. Though that certainly qualifies and is yet another definition of epic. Some stories about people--their relationships or just their lives in general--can seem epic, even if the scope of the person's life or the relationship is small compared to the rest of the world. Maybe it's just me, but Pride and Prejudice comes to mind. In the grand scheme of things, Elizabeth and Mr. Darcy's romance isn't all that significant. But while you're reading the book or watching the movie, it becomes epic because of how well we get to know the characters and how high the personal stakes are. I think this kind of relationship can become epic for readers because of how strong the emotions are, and how almost everyone can relate to deep, well-told emotions.
Those are the three that come to mind right now, but I want to hear from everyone else. What aspects of stories (that may not fit the traditional definition) do you think can be epic?