In a nutshell
Calling something a graphic novel is not just a fancy way of saying “comic”. There is a very distinct difference between the two. Visual novels are much longer and tend to be much more complex. While a comic tells a story across many subjects, graphic novels more often have their storylines condensed into just one or two books.
The whole bushel
Accuse someone reading a graphic novel of being interested in comics and you will at least likely get a dirty look (or a lecture at worst). They might look the same at first glance, but are actually very different types of story media.
Both comics and graphic novels use a combination of illustrations and words to tell a story. This story can be anything, be it fiction or non-fiction, the story of a superhero or a zombie apocalypse. The difference isn̵
Comics are serialized stories; Most of them are relatively short and tell the story of the book’s heroes and heroines over a long period of time. There are usually many, many editions of a successful comic book, and the stories unfold over months and sometimes years.
Visual novels are longer works that tell a single story from beginning to end. (Sometimes successful comics are collected and packaged in a graphic novel format.) Because stories don’t have to be broken down across myriad topics, plots can often be more complex and detailed, since readers don’t have to remember details for months to years as they read. Manga is a kind of graphic novel, a Japanese graphic novel that is read top to bottom and right to left as that is how the Japanese language is read.
Graphic novels actually predate comics. It is believed that the first graphic novel ever published was the 1783 adaptation by Gottfried August Burger Lenardo and Blandine. The 160-picture work, illustrated by Joseph Franz von Goez, tells the story of two unhappy lovers. Blandine, the king’s daughter, falls in love with her father’s loyal courtier, Lenardo, and marries him. Her father promises her to someone else, kills Lenardo and tells his daughter about her husband’s death by sending her three messengers with a ring, a letter and an urn with her husband’s heart. She goes mad, of course, and dies of grief.
Although individual comics have been around for centuries, comics are a relative newcomer to the literary world. Single-panel comics were published in newspapers and broadsheets since the mid-18th century, and comics became popular in the late 19th century. However, it is widely believed that comics as we know them today originated in Funny on parade in 1933 and Action Comics # 1 (the first appearance of Superman) in 1938.
Comics conquered the market for decades until graphic novels rose in popularity again. In the 1980s and 1990s, British writers like Alan Moore and Neil Gaiman brought graphic novels back to the mainstream market. Graphic novels enjoyed subterranean popularity at a time when artists and writers tried to make clear the separation between media. Graphic novels had a reputation for being grainy, explicit, and aimed at a mature audience, while comics became increasingly popular. Ironically, comics have long had their own stigma of being, at best, a childish, immature, guilty pleasure.
Fortunately, thanks to the large format adaptations of graphic novels and comics, some of this stigma is being removed after decades.
Show me the proof
Heritage Auction Galleries: A Brief History of the Comics
Lenardo and Blandine, illustrated by Joseph Franz von Goez
Get graphics: The world in words and pictures
Graphic Novels: History and Basics