Pipelining is a technique used in computer architecture to overlap the execution of multiple instructions in a pipeline, allowing multiple instructions to be processed simultaneously and improving the overall throughput of the system. Pipelining breaks down the instruction execution into multiple stages, such as fetch, decode, execute, and write-back, and each stage is processed independently by different parts of the CPU. This allows multiple instructions to be in different stages of execution at the same time, resulting in faster instruction execution and improved performance.