The former Soviet Union and those (formerly) communist states that were politically and economically allied with it are often informally called the Second World. The term developed after World War II to distinguish communist bloc states from powerful capitalist states (First World) and from smaller, nonaligned developing states (Third World). These terms developed as a part of theories that the world's countries together made up a single dynamic system in which these three sectors interacted. Although the term is often used to indicate countries and regions of intermediate economic strength, its proper meaning has to do with political economy, or the politics of communist-socialist economics. In recent years, with the shrinking role and then disintegration of the communist bloc, the term has become much less common than those of First and Third Worlds.