Least Recently Used (LRU) is a cache management algorithm that prioritizes keeping the most recently accessed data in memory. When the cache reaches its limit, LRU removes the least recently used items to make space for new data. This approach helps improve performance by ensuring that frequently accessed information remains readily available. In computer systems, LRU is commonly used in various applications, such as operating systems and database management systems. By tracking the order of data access, LRU efficiently manages memory and optimizes resource usage, ultimately enhancing the overall speed and responsiveness of the system.