Satire is a form in art or writing which ridicules either a person, government, or an institution, often through the use of humour. Satire can either be in paintings, plays, books, songs, TV or movies. It also is used to stereotype people.
Satire was used long ago, even as long ago as the Ancient Greeks. It was widely known in Elizabethan times. Swift used satire in his book Gulliver's Travels to make fun of people’s stupidity. Works like The Beggar’s Opera (1728) used satire to show how silly the politicians of the time were. The German playwright Bertolt Brecht used a lot of satire, as did Peter Cook. More recently Jon Stewart and other comedians use it frequently.
Satire often points out ironic or bad things that powerful people are doing. Its adjective is satirical.