Wiktionary
n. (context arts English) A Stalinist idealization of the dictatorship of the proletariat applied to art that used realistic techniques to show the struggle for socialism in a positive and optimistic manner
Wikipedia
Socialist realism is a style of realistic art that was developed in the Soviet Union and became a dominant style in various other socialist countries. Socialist realism is characterized by the glorified depiction of communist values, such as the emancipation of the proletariat, by means of realistic imagery. Although related, it should not be confused with social realism, a type of art that realistically depicts subjects of social concern.
Socialist realism was the predominant form of approved art in the Soviet Union from its development in the early 1920s to its eventual fall from popularity in the late 1960s. While other countries have employed a prescribed canon of art, socialist realism in Soviet Union persisted longer and was more restricted than elsewhere in Europe.