In the visual arts, the way elements are arranged within the frame is important. Whatever it is the artist is trying to depict can be defined by not only the objects themselves, but the relationship between them.
Composition
In the realm of fine art, Dictionary.com defines composition as "the organization or grouping of the different parts of a work of art so as to achieve a unified whole."
Juxtaposition
One of the elements of composition is juxtaposition, where elements are put near each other for the purpose of comparison or contrast.
Juxtaposition for Comparison
For instance, when an artist wants to illustrate an overriding theme, he or she may put similar objects together to allow the viewer to extract that theme.
Juxtaposition for Contrast
In other situations, the artist may want to make a point with irony. In that case, he or she may elect to put two or more objects together that have opposite connotations or symbolize opposite concepts.
Juxtaposition in other Arts
The idea of juxtaposition is a visual one, but it works for other fields too, like literature. Sometimes writers will put two characters with different qualities next to each other to define their personalities, or write about two settings to create a complex context or a progression of an idea.
