The MOESI Protocol is a cache coherence protocol used in multiprocessor systems to maintain consistency among caches. It ensures that multiple processors can access shared data without conflicts, allowing them to work efficiently. The acronym stands for the five states a cache line can be in: Modified, Owned, Exclusive, Shared, and Invalid. In the MOESI Protocol, each cache line can transition between these states based on operations like reads and writes. For example, if a processor modifies a cache line, it enters the Modified state, indicating that it has the only valid copy. This protocol helps prevent stale data and ensures that all processors have the most up-to-date information.