V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

CGM
       Computer Graphics Metafile (ISO 8632)


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

Computer Graphics Metafile
CGM

    (CGM) A standard file format for
   storage and communication of graphical information, widely
   used on personal computers and accepted by desktop
   publishing and technical illustration systems.

   MIME type: image/cgm.

   ANSI/ISO 8632-1987.  Worked on by the ISO/IEC group
   JTC1/SC24.

   CGM Open Consortium (http://cgmopen.org/).

   See also: WebCGM.

   (1999-02-16)