A service composition is a coordinated aggregate of services. As explained on the Effects of Service-Orientation on the Enterprise page, a composition of services is comparable to a traditional application in that its functional scope is usually associated with the automation of a parent business process.
The consistent application of service-orientation design principles leads to the creation of services with functional contexts that are agnostic to any one business process. These agnostic services are therefore capable of participating in multiple service compositions.
As further discussed at Service-Orientation Principles, the ability for a service to be naturally and repeatedly composable is fundamental to attaining several of the strategic goals of service-oriented computing. Therefore, many of the design characteristics that distinguish a service enable it to effectively participate in service compositions.
Figure 1 – The symbol comprised of three connected spheres represents a service composition. Other, more detailed representations are based on the use of chorded circle symbols (below) to specifically identify which service capabilities are actually being composed.