According to getgraphic.org:
"Graphic Novel" is a format, not a genre. Graphic novels can be fiction, non-fiction, history, fantasy, or anything in-between.
Graphic novels are similar to comic books because they use sequential art to tell a story. Unlike comic books, graphic novels are generally stand-alone stories with more complex plots. Collections of short stories that have been previously published as individual comic books are also considered graphic novels.
Get much more information about graphic novels by visiting their site: getgraphic