Modernism, in its broadest definition, is modern thought, character, or practice. More specifically, the term describes the modernist movement in the arts, its set of cultural tendencies and associated cultural movements, originally arising from wide-scale and far-reaching changes to Western society in the late 19th and early 20th centuries. In particular the development of modern industrial societies and the rapid growth of cities, followed then by the horror of World War I, were among the factors that shaped Modernism. Related terms are modern, modernist, contemporary, and postmodern.