Speech balloon in the context of "Gag cartoon"

Comics are a medium used to express ideas with images, often combined with text or other visual information. It typically takes the form of a sequence of panels of images. Textual devices such as speech balloons, captions, and onomatopoeia can indicate dialogue, narration, sound effects, or other information. There is no consensus among theorists and historians on a definition of comics; some emphasize the combination of images and text, some sequentiality or other image relations, and others historical aspects such as mass reproduction or the use of recurring characters. Cartooning and other forms of illustration are the most common means of image-making in comics. Photo comics are a form that uses photographic images. Common forms include comic strips, editorial and gag cartoons, and comic books. Since the late 20th century, bound volumes such as graphic novels and comic albums have become increasingly common, along with webcomics.

The history of comics has followed different paths in different cultures. Scholars have posited a pre-history as far back as the Lascaux cave paintings. By the mid-20th century, comics flourished, particularly in the United States, western Europe (especially France and Belgium), and Japan. The history of European comics is often traced to Rodolphe Töpffer's cartoon strips of the 1830s, while Wilhelm Busch and his Max and Moritz also had a global impact from 1865 on, and became popular following the success in the 1930s of strips and books such as The Adventures of Tintin. American comics emerged as a mass medium in the early 20th century with the advent of newspaper comic strips; magazine-style comic books followed in the 1930s, and the superhero genre became prominent after Superman appeared in 1938. Histories of Japanese comics (manga) propose origins as early as the 12th century. Japanese comics are generally held separate from the evolution of Euro-American comics, and Western comic art probably originated in 17th-century Italy. Modern Japanese comic strips emerged in the early 20th century, and the output of comic magazines and books rapidly expanded in the post-World War II era (1945–) with the popularity of cartoonists such as Osamu Tezuka. Comics has had a lowbrow reputation for much of its history, but towards the end of the 20th century, it began to find greater acceptance with the public and academics.

A comic strip (also known as a strip cartoon) is a sequence of cartoons, arranged in interrelated panels to display brief humor or form a narrative, often serialized, with text in balloons and captions. Traditionally, throughout the 20th and into the 21st century, these have been published in newspapers and magazines, with daily horizontal strips printed in black-and-white in newspapers, while Sunday papers offered longer sequences in special color comics sections. With the advent of the internet, online comic strips began to appear as webcomics.

Most strips are written and drawn by a comics artist, known as a cartoonist. As the word "comic" implies, strips are frequently humorous but may also be dramatic or instructional. Examples of gag-a-day strips are Blondie, Bringing Up Father, Marmaduke, and Pearls Before Swine. In the late 1920s, comic strips expanded from their mirthful origins to feature adventure stories, as seen in Popeye, Captain Easy, Buck Rogers, Tarzan, and Terry and the Pirates. In the 1940s, soap-opera-continuity strips such as Judge Parker and Mary Worth gained popularity. Because "comic" strips are not always funny, cartoonist Will Eisner has suggested that sequential art would be a better genre-neutral name.

Silent comics (or pantomime comics) are comics which are delivered in mime. They make use of little or no dialogue, speech balloons or captions written underneath the images. Instead, the stories or gags are told entirely through pictures.