The Jargon File (version 4.4.7, 29 Dec 2003):

retrocomputing
 /ret'?roh?k@m?pyoo'ting/, n.

    Refers to emulations of way-behind-the-state-of-the-art hardware or
    software, or implementations of never-was-state-of-the-art; esp. if such
    implementations are elaborate practical jokes and/or parodies, written
    mostly for hack value, of more ?serious? designs. Perhaps the most widely
    distributed retrocomputing utility was the pnch(6) or bcd(6) program on V7
    and other early Unix versions, which would accept up to 80 characters of
    text argument and display the corresponding pattern in punched card code.
    Other well-known retrocomputing hacks have included the programming
    language INTERCAL, a JCL-emulating shell for Unix, the
    card-punch-emulating editor named 029, and various elaborate PDP-11
    hardware emulators and RT-11 OS emulators written just to keep an old,
    sourceless Zork binary running.

    A tasty selection of retrocomputing programs are made available at the
    Retrocomputing Museum, http://www.catb.org/retro/.


The Free On-line Dictionary of Computing (30 December 2018):

retrocomputing

   /ret'-roh-k*m-pyoo'ting/ Refers to emulations of
   way-behind-the-state-of-the-art hardware or software, or
   implementations of never-was-state-of-the-art; especially if
   such implementations are elaborate practical jokes and/or
   parodies, written mostly for hack value, of more "serious"
   designs.  Perhaps the most widely distributed retrocomputing
   utility was the "pnch(6)" or "bcd(6)" program on V7 and other
   early Unix versions, which would accept up to 80 characters of
   text argument and display the corresponding pattern in
   punched card code.  Other well-known retrocomputing hacks
   have included the programming language INTERCAL, a
   JCL-emulating shell for Unix, the card-punch-emulating
   editor named 029, and various elaborate PDP-11 hardware
   emulators and RT-11 OS emulators written just to keep an old,
   sourceless Zork binary running.

   [Jargon File]