Bolshevik : a member of the Bolshevik Party lead by Lenin. It later became the Communist Party. It believed that a small group of intellectuals should lead the fight for the working class as they had the education to know what to do and the poor did not.
Cheka : the name given to Lenin's secret police. It later became the KGB.
Communism : a belief developed by Karl Marx. It basically stated that everybody is equal and no-one was better than anybody else. One person's luxury lifestyle, lead to another person's poverty and exploitation.
Five Year Plans : the name given to Stalin's industrial plans for the USSR so that she could catch up quickly with the west.
Gulag : the name given to Stalin's prison camps. Many were built in the harshest of conditions - frequently Siberia. The treatment given to these prisoners was harsh and extreme.
Personality Cult : when a country's leader gets the people of that country to all but worship hem/her. Cities, rivers, regions etc are named after him and towns and cities are littered with huge posters of the leader. Stalin tried to do this in Russia.
Purges : the name given to the time when Stalin shot or sent to the gulags those who he felt opposed his rule. Millions were dealt with in this manner after show trials.
Reds : the name given to anything associated with the Bolsheviks; such as the Red Army during the Civil War.
Tsar : Russia's equivalent of king such as in Tsar Nicholas II.
War Communism : the name given to the policy introduced by Lenin at the start of the civil war whereby the Cheka confiscated whatever it needed with regards to food, equipment etc. Those who opposed the Cheka were shot as "enemies of the state".
Whites : the name given to the groups that opposed the Bolsheviks after the overthrow of the Provisional Government and during the Civil War.