Satire is loosely defined as art that ridicules a specific topic in order to provoke readers into changing their opinion of it. By attacking what they see as human folly, satirists usually imply their own opinions on how the thing being attacked can be improved.
Perhaps the most famous work of British satire is Jonathan Swift's Gulliver's Travels (1726), where the inhabitants of the different lands Gulliver visits embody what Swift saw as the prominent vices and corruptions of his time.
Like Gulliver's Travels, George Orwell's Animal Farm is a satirical novel in which Orwell, like Swift, attacks what he saw as some of the prominent follies of his time. Broadly speaking, Animal Farm satirizes politicians, specifically their rhetoric, ability to manipulate others, and insatiable lust for power.