The Free On-line Dictionary of Computing (19 January 2023):

GOSMACS

   /goz'maks/ Gosling Emacs.  The first Emacs implementation in
   C, predating but now largely eclipsed by GNU Emacs.
   Originally freeware; a commercial version is now modestly
   popular as UniPress Emacs.  The author (James Gosling) went
   on to invent NeWS.

   [Jargon File]


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

GOSMACS
 /goz'maks/, n.

    [contraction of ‘Gosling EMACS’] The first EMACS-in-C implementation,
    predating but now largely eclipsed by GNUMACS. Originally freeware; a
    commercial version was modestly popular as ‘UniPress EMACS’ during the
    1980s. The author, James Gosling, went on to invent NeWS and the
    programming language Java; the latter earned him demigod status.