A comic can mean a few related things:

1. A type of story told through a series of pictures with words, usually in boxes called panels. Comics combine drawings with dialogue bubbles and captions to tell stories. Some comics are funny, like the Sunday newspaper strips about Garfield or Calvin and Hobbes, but many tell serious adventures, mysteries, or superhero tales. Longer, book-length comics are often called graphic novels. Japanese comics, called manga, follow their own distinct style and traditions.
2. Something or someone that makes people laugh. A comic performance gets the audience chuckling, and a comic actor specializes in humor. If your friend has great comic timing, they know exactly when to deliver a joke for maximum laughs. The word comic in this sense suggests something lighter than slapstick but funnier than merely amusing.