A pipeline is several programs simultaneously processing the same input/output stream.
It is the data processing elements set (functions, processes, threads) in chain, series connection where output of one element is input of the other. Its analogy is similar to physical pipeline. Some buffering is allowed between consecutive elements. The information flowing through the pipeline is a stream of bits, bytes, records.
This can be one-directional and bi-directional. These are frequently implemented in multitasking Operating Systems, many processes are launched at same time.
