"The System Specification is the final work product produced by the system and
requirements engineer. It serves as the foundation for hardware engineering, software
engineering, database engineering, and human engineering. It describes the
function and performance of a computer-based system and the constraints that will
govern its development. The specification bounds each allocated system element.
The System Specification also describes the information (data and control) that is input
to and output from the system." - Pressman Software Engeneering
Especificação de requisitos não é uma atividade do processo de software. É, na verdade, um artefato produzido pela engenharia de requisitos.