A comedy is funny business — it can be an amusing play or movie with a happy ending, or something that happened that made you laugh.
A comedy tries to entertain through honest depictions of life, unlike burlesque, which aims to please its audience through satire, or farce, which relies on absurdity. Charlie Chaplin observed, “Life is a tragedy when seen in close-up, but a comedy in long-shot.” In other words (of disputed origin), "Tragedy plus time equals comedy." When you slipped on that banana peel and broke your nose? Tragedy! But once you got better, you realized it was actually kind of funny.