A literary movement is defined by a group of writers with shared ideas about a number of things ranging from: style, content, philosophy, sociological concerns, art, culture, etc. A literary movement can be in opposition a current literary movement. For example, in England, Romanticism (approximately 1789-1832) was seen as a reaction to Neoclassical literature (approximately 1660-1789). Dates of literary periods are always debated.
The dates of movements are often historically influenced, or sometimes for the sake of efficiency, these periods are often synced with significant historical events. For instance, the beginning of Romanticism is sometimes listed as 1789, the first year of the French Revolution. There is added significance in that the French Revolution marked the beginning of the decline of monarchies with the rise of democracy, while Romanticism celebrated individualism (which would have more impact in a democracy than in a monarchy). In this case, the movement (Romanticism) was influenced by, and reciprocally influenced, the political effects of the French Revolution.
This is not to say that all Romanticism can only have occurred in this time period. There are writers today who could be defined as Romanticists. It is just that the movement formed, flourished, and was defined during this time.
There are also movements within movements. Modernism (approximately late 19th century - the 1960s) contains many similar and/or different movements: Magical Realism, Surrealism, Futurism, Imagism, and Theatre of the Absurd - to name a few.
Broadly defined, literary movements are trends within literary periods in which literature is unified by shared intellectual, linguistic, religious, and artistic influences [See Wheeler, Earlier/Later Periods of Literature]. Literary movement describes a collective upsurge of anideological or critical approach to literature that is different from others before it and usually leads to new directions after it. Some instances of specific literary movements within literary periods are Captivity Narratives, American Southern Gothic, Naturalism, and Realism. There are many other literary movements.
A current movement is metafiction in which the narrator or writer exposes within the narrative that s/he is the narrator of the narrative or the writer of the narrative through such means as the narrator exclaiming about the difficulties of constructing rising action or the writer intruding to rewind, as it were, and claim the right to and then proceed to rewrite a scene. Other literary movements are Magic Realism, Bloomsbury Group, Beat, Literature of the Absurd, Harlem Renaissance, Pre-Raphaelites and Romanticism. For more information on the many specific literary movements, refer to the links below.
Is there a relation between connotative and denotative language and neoclassicism and romanticism?