Relevance in the context of legal discovery refers to information or evidence that is directly related to the facts of a case and could influence the outcome of legal proceedings. It plays a crucial role in determining what information can be obtained during discovery, ensuring that parties have access to data that can substantiate their claims or defenses. The concept is essential for maintaining fairness in the legal process, as it helps to limit the scope of inquiries to those matters that genuinely matter to the case at hand.