Eliciting, analyzing, validating, verifying, and managing requirements have consistently been recognized as key activities of business analysis. Business analysts also support the definition of design. 
Requirements are focused on the need; designs are focused on the solution. The distinction between requirements and designs is not always clear. The same techniques are used to elicit, model, and analyze both. A requirement leads to a design which in turn may drive the discovery and analysis of more requirements. The shift in focus is often subtle.
Concepts: BACCM Terms Classifications Stakeholders Requirements and Designs