A comedy is any sort of performance intended to cause laughter or the emotions associated with laughter. For ancient Greeks and Romans a comedy was a stage-play with a happy ending. In the Middle Ages, the term expanded to include narrative poems with happy endings and a lighter tone. In this sense Dante used the term in the title of his poem, La Divina Commedia.
The phenomena connected with laughter and that which provokes it has been carefully investigated by psychologists and agreed upon the predominating characteristics are incongruity or contrast in the object, and shock or emotional seizure on the part of the subject. It has also been held that the feeling of superiority is an essential factor: thus Thomas Hobbes speaks of laughter as a “sudden glory.” Modern investigators have paid much attention to the origin both of laughter and of smiling, as well as the development of the “play instinct” and its emotional expression.
Much comedy contains variations on the elements of surprise, incongruity, conflict, repetitiveness, and the effect of opposite expectations, but there are many recognized genres of comedy. Satire and political satire use ironic comedy used to portray persons or social institutions as ridiculous or corrupt, thus alienating their audience from the object of humor.
ABWAG Extensive resource on comedy and how to play it.
Dallas Baptist University Useful definition of caricature.
Dallas Baptist University Overview of the differences between wit and humour in comedy.
The Drama Teacher Overview of comedy at Justin Cash’s Drama teacher resource website.
Wikipedia Definitions of various forms of comedy with useful links to more articles.