Workflow Application

A workflow application is where various applications, components, and people must be involved in the processing of data to complete an instance of a process. For example, consider a purchase order that moves through various departments for authorization and eventual purchase. The orders may be treated as messages, which are put into various queues for processing. It is critical that the state of the queues are captured.

A workflow process involves constant change and update. You can introduce new components into the operation without changing any code.
There are two ways of developing workflow applications. The first one is to design workflow models in a dedicated language and then to link the tasks in these models to worklist handlers (for human tasks) or software applications (for automated tasks).

Workflow languages usually come with an associated graphical notation, but some are textual or XML-based. Languages that can be used for workflow definition in this way include:
Dedicated workflow specification languages:
1. XPDL
2. YAWL
3. SCUFL
Executable process definition languages based on Web Services:
1. BPEL
2. BPML
3. WSFL
4. XLANG
5. Wf-XML
6. SWSL

Ref: wikipedia