A requirement is a function that a product, process, or system must do or a quality it must possess. Requirements are a crucial component of the solution that a Business Analyst proposes. They are one of the components that drive the BA to create the solutions that they bring to the table.
Typically, the SMART framework applies to goals. But it has been borrowed and re-adjusted to apply to requirements, making them Specific, Measurable, Attainable, Reasonable, and Traceable.

Developing SMART requirements is one of the core concepts a Business Analyst must know to be successful in their projects. If you are ready to learn more about requirements, as well as all the other foundational business analysis concepts, take a look at my Business Analysis Fundamentals course (discounted for a limited time!).
And always remember, it’s not a good requirement until it’s a SMART requirement!
– Written by Jeremy Aschenbrenner, The BA Guide