"Composition" refers to the particular manner in which something is arranged. This noun applies to diverse fields, including literature, visual arts, chemistry and demographics. The verb "compose" is the word's root.
When describing art and literature, "composition" (like the term "design") may refer to the act of arrangement as well as the end product. For example, "He excelled at composition, so it was no surprise that the gallery chose to showcase his latest composition." Students learn about the composition of metallic compounds in chemistry and the changing racial composition of urban areas in social science. Depending on the usage, "arrangement," "number," "design" and "work" are synonyms of composition.