"Graphic Novel" is a type of format (such as novel or picture book, magazine etc...), not a genre (such as fantasy, science fiction etc...). 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.