Source : Free On-Line Dictionary of Computing

light-weight process
     
         (LWP) A single-threaded
        sub-process which, unlike a {thread}, has its own {process
        identifier} and may also differ in its inheritance and
        controlling features.
     
        Several {operating systems}, e.g. {SunOS} 5.x, provide {system
        calls} for creating and controlling LWPs.
     
        (1996-02-22)