Genre Fiction: Definition for Creative Writers
"Webster's" defines "genre" as "a kind; sort; type: said of works of literature, art, etc." On this site, and in general, "genre fiction" refers to nonliterary works and include the categories of mystery, science fiction, fantasy, romance, western, and horror. Pure genre fiction is usually "one note" and works solely on the level it is intended. It does not necessarily have complex characters and is usually not character-driven, but plot-driven. Genre fiction tends to be written and read primarily for entertainment.
Though it may certainly aspire to and attain other goals, entertainment is the primary objective. However, as David Mamet points out in his essay, "The Humble Genre Novel, Sometimes Full of Genius," many works now considered great literature were originally genre novels. Raymond Chandler, of course, exemplifies this phenomenon. Mamet goes so far as to open his essay with the line, "For the past thirty years the greatest novelists writing in English have been genre writers."
Genre Versus Literary Fiction
If you're unsure whether your story or novel can be considered both genre fiction and literary fiction, it's worthwhile trying both camps. It certainly doesn't hurt to have more options for publishing your work, especially if you're not too proud. If you read enough genre and literary genre, you should be able to tell the difference between the two. If you cannot, keep writing and reading. It is important that you know what kind of writer you are, and how you should market yourself.
In order for genre fiction to be literary as well, the writing must transcend the genre. This means that the writing must work on a literary level as well as a genre level. Although genre writing focuses mostly on story and world-building as opposed to the internal lives of characters, when a writer can combine both of these, they often come up with something completely new and interesting. Author Neil Gaiman's writing is an example of this. Much of Stephen King's work is also considered in the literary genre.
There are many authors working now on transcending the genre, through zombie stories, young adult literature, and science fiction. Speculative fiction is also a very popular genre as well. Primarily literary writers such as Sam Lipsyte and Jennifer Egan have written sci-fi stories for The New Yorker's Science Fiction Issue. This acceptance (and inclusion and encouragement) of genre writing is an exciting addition for up and coming authors interested in writing literary genre.
It is important, however, for young writers to remember that writing literary genre fiction should adhere to the same "rules" as writing regular fiction. Unless writing specifically for a genre-loving audience, one should always aim to make their work multi-dimensional, complex and thought-provoking.
If you are set on writing pure genre fiction, look for imprints and agents specifically catering to your specific interest. You do not want to waste your time attempting to publish a piece of fiction that is specifically designed for a pure genre audience with a publishing house that does not publish the genre you are writing or is not looking for pure genre fiction.