Definition
A document describing the business, operational and functional needs that a system must satisfy from the user perspective.
Human Explanation
URS answers: what do we need the system to do?
Why it Matters
It provides a foundation for design, Validation and later confirmation that the delivered system meets its intended use.
Conceptual Boundary
URS states needs and acceptance expectations, not the technical means of implementation.
Practical Perspective
Requirements should be clear, testable, prioritised, approved and traceable through the lifecycle.