What is allegory in Animal Farm?

The story of Animal Farm is an allegory of the events in Russia after the downfall of Tsar Nicholas III (1910's to 1940's). The characters and events in the story all represent those during this time. Major represents Karl Marx, Animalism is similar to communism, Napoleon represents Stalin, Snowball represents Trotsky, Squealer symbolises propaganda, Mr Jones represents the Tsar when he was in power and other things.

Hope that helps!