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.