The Meaning of "American Literature"

Here's a question that bothers some people late at night when they're standing in front of the open refrigerator door, their midnight-snack run interrupted by an unwanted thought that has been nagging at the back of their mind all day:

- Just what does "American Literature" mean, anyway!? -

Now if that person happens to hold a degree in English, they may have some luck: they know they've got to understand each of those largish words separately (it's late, after all, and half their attention is focused on the cheese, inspecting it for mold). "Literature" is perhaps the easier of the two. To the English student, "literature" denotes a collection of art. It has connotations, too: "literature" is usually thought of as written art, and often considered to be somehow superior to other examples of the same art form(s). This means that "American Literature" must be a collection of American art, with an emphasis on well-written examples.

The only thing left standing in the way of the student's understanding is that first and more formidable word, "American." What does that mean? But it's late, and they've got the cheese in their mouth, and at this point most people shamble off to bed, their nocturnal hunger sated. Yet the refrigerator door is left hanging open, just like this question -

What does "American" mean?