Source : Free On-Line Dictionary of Computing

IBM PCjr
     
         ({IBM PC} Junior) A {floppy disk}-based home
        computer with an {Intel 8088} {CPU} and a {chiclet keyboard},
        released in November 1983.  The PCjr could be expanded to have
        two floppy drives and 640 kilobytes of {RAM} using {sidecar}s.
        Some even had a {mouse} and could run drawing programs with
        {popup menu}s.
     
        (1995-10-06)