Please explain the term "Postmodernism."

The term postmodern is described by Merriam Websteer as meaning either "of, relating to, or being an era after a modern one" or "of, relating to, or being any of various movements in reaction to modernism that are typically characterized by a return to traditional materials and forms (as in architecture) or by ironic self-reference and absurdity (as in literature)", or finally "of, relating to, or being a theory that involves a radical reappraisal of modern assumptions about culture, identity, history, or language".

Postmodernism was originally a reaction to modernism, largely influenced by the Western European "disillusionment" induced by World WarII. Both World Wars contributed to postmodernism; it is with the end of the Second World War that recognizably postmodernist attitudes begin to emerge. Postmodernism tends to refer to a cultural, intellectual, or artistic state lacking a clear central hierarchy or organizing principle and embodying extreme complexity, contradiction, ambiguity, diversity, interconnectedness or interreferentiality, in a way that is often indistinguishable from a parody of itself.

The term was applied to a whole host of movements, many in art, music, and literature, that reacted against modernism, and are typically marked by revival of traditional elements and techniques. Postmodernist ideas in  philosohy and the analysis of culture and society expanded the importance of criticaltheory and has been the point of departure for works of literature architecture, and design as well as being visible in marketing/business and the interpretation of history   and culture, starting in the late 20th century.

Art and literature of the early part of the 20th century play a significant part in shaping the character of postmodern culture. Dadaism attacked notions of high art in an attempt to break down the distinctions between high and low culture; Surrealism  further developed concepts of Dadaism to celebrate the flow of the subconscious with influential techniques such as automatism and nonsensical juxtapositions.