The term surrealism refers both to the 1920s artistic movement celebrating imagination over realism and, more broadly, to the incorporation of fantasy and strangeness in a work.
From A Poet’s Glossary
The following definition of the term surrealism is reprinted from A Poet's Glossary by Edward Hirsch.
The convulsive phenomenon known as Dadaism was revitalized and transformed into the more durable movement of surrealism in France in the 1920s. The term surréaliste was coined by Guillaume Apollinaire in 1917 to suggest a dramatic attempt to go beyond the limits of an agreed-upon “reality.” André Breton used the term surrealism (“superrealism,” or “above reality”) in 1924 in the first of three manifestoes. (“I believe in the future resolution of these two states, dream and reality, which are seemingly so contradictory, into a kind of absolute reality, a surreality.”) The surrealists were apostles of what Breton called “beloved imagination.” They hungered for the marvelous and believed in the revolutionary power of erotic desire and “mad love,” of dreams, fantasies, and hallucinations. They freed the mind from the shackles of rational logic and explored the subterranean depths, the deeper reality, of the unconscious, the night mind. They cultivated a condition of lucid trance or delirium and experimented with automatic writing or automatism—that is, writing attempted without any conscious control, as under hypnosis. The surrealists courted disorder and believed in the possibilities of chance, of emotion induced by free association and surprising juxtapositions, as when Comte de Lautréamont had called something “beautiful as the chance meeting, on a dissection table, of a sewing machine and an umbrella.”
The surrealists were scandalized by the repressiveness of society, and they scandalized society in return. They wanted to change the human condition. A practical, political dimension entered the movement in 1925, linking economic revolution with mental liberation (priority was always given to mental experiments), and a problematic relationship developed with the Communist party, which never quite flowered into a full-scale alliance.
The surrealists’ true goal was inner freedom. Breton states in the second manifesto (1929):
The idea of Surrealism tends simply to the total recuperation of our psychic forces by a means which is no other than a vertiginous descent within ourselves, the systematic illumination of hidden places, the progressive darkening of all other places, the perpetual rambling in the depths of the forbidden zone.
The surrealists reiterated their faith in love, liberty, and the arts. (Robert Desnos called one work La liberté ou l’amour!, 1927; Paul Éluard entitled another L’amour la poésie, 1929.)
The major surrealists in poetry: Breton, Louis Aragon, Desnos, Éluard, Philippe Soupault, Benjamin Péret. In the visual arts: Man Ray, Francis Picabia, Giorgio de Chirico, André Masson, Yves Tanguy, Max Ernst, Salvador Dali. In film: Luis Buñuel. In theater: Antonin Artaud. Breton acknowledged that surrealism was the “prehensile tail” of romanticism. The surrealists recognized their ongoing debts to the Marquis de Sade (1740–1814) and Gérard de Nerval (1808–1855), who first used the term supernaturalism, to Charles Baudelaire (1821–1867) and Stéphane Mallarmé (1842–1898), who considered the poet a magician, to Arthur Rimbaud (1854–1891), Apollinaire (1880–1918), and Sigmund Freud (1856–1939).
Surrealism dissolved as a cohesive movement in the late 1930s, but the United States benefited from the wartime presence of some of the leading surrealist figures, such as Breton and Ernst. In a broad sense, surrealism means a love of dreams and fantasies, a taste for strange marvels and black humor, an eagerness to take the vertiginous descent into the self in quest of the secret forces of the psyche, a faith in the value of chance encounters and free play, a belief in the liberating powers of eros, of beloved imagination.