In the context of unjust enrichment, loss refers to the detriment or disadvantage suffered by a party due to another party's improper acquisition or use of their property or benefits. This concept is critical in determining whether a person has been unjustly enriched at the expense of another and serves as a foundational element for claims seeking restitution. Establishing loss helps to assess the fairness of retaining benefits without compensation, emphasizing the need for equity in transactions and interactions.