Functional Requirements

A functional requirement specifies what a deployed product/system must do.

Note, (a) a system may have more than one requirement, and (b) each requirement must have at least one criterion. The Volere Specification defines a criterion, i.e., fit criterion, as an objective measure

"… for defining the meaning of a requirement, and eventually testing whether a given solution satisfies the original requirement." (Volere Specification)

The deployment goal dictates what the product/system will be, and the functional requirements thereof.