In comics, the term "ongoing series" is used in contrast to limited series (a series intended to end after a certain number of issues), a one shot (a comic book which is not a part of an ongoing series), a graphic novel, or a trade paperback. However, a series of graphic novels may be considered ongoing as well. The term may informally refer to a finite series if the number of issues is predetermined. If a series ceases to be published, but may be published again, it is called "on hiatus." Many series are placed "on hiatus" but do not return even after several years.