DuckCorp Dico

Found one definition

1.                 From The Free On-line Dictionary of Computing (19 January 2023):
                   
   
   
                   
                     
   REM
      <programming> (From "remark") The keyword used in BASIC to
      introduce a comment (which continues to the end of the
      line).  MS-DOS probably borrowed it from BASIC.  Might be
      used in the form "REM out" meaning to comment out.
      (1998-04-27)