Conditions that a software product must satisfy to be accepted by a user, customer, or other stakeholder.

An analysis model that shows a dynamic view of a system by depicting the flow from one activity to another. Similar to a flowchart.

A person, software system, or hardware device that interacts with a system to achieve a useful goal. Also called a user role.

See requirements allocation.

A scenario in a use case that leads to success (accomplishing the actor’s goal) but involves a variation from the normal course in the specifics of the task or of the actor’s interaction with the system. Also known as an alternative course.

The process of classifying requirements information into various categories, evaluating requirements for desirable qualities, representing requirements in different forms, deriving detailed requirements from high-level requirements, negotiating priorities, and so on.

See requirements analyst.

The structure of a software-containing system, including the software and hardware components that make up the system, the interfaces and relationships between those components, and the component behaviors that are visible to other components.

A statement that is believed to be true in the absence of proof or definitive knowledge.

See requirement attribute.