The definition activity is where business features are turned into buildable instructions for the development team.  Information is solicited from the business experts and translated into requirements, scenarios, user stories or features.

The definition and planning activities frequently overlap.  In fact, many successful development methodologies iteratively define requirements; that is, the definition process may coexist with other application development activities and iteratively occur before releasing a product.  The results of the definition is used to drive design and construction activities.  The definition usually directly correlates to test cases in the test activity.

Sub Activities

Although most organizations will have some variants, definition activities typically include the following:

• Creating requirement artifacts including stories, scenarios, features, use cases or specifications.
• Decomposing requirements.
• Defining quality of service requirements.

The definition activity usually includes prioritization and can directly overlap with the planning activity.