MPI, or Message Passing Interface, is a standardized and portable communication protocol used in parallel computing. It allows multiple processes to communicate with each other, enabling efficient data exchange and coordination in high-performance computing environments. MPI is widely used in scientific computing, simulations, and large-scale data processing. MPI provides a set of functions that facilitate the sending and receiving of messages between processes, regardless of their location in a distributed system. This makes it easier for developers to write programs that can run on various hardware configurations, from small clusters to supercomputers, while ensuring scalability and performance.