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

parm
 /parm/, n.

    Further-compressed form of param. This term is an IBMism, and written use
    is almost unknown outside IBM shops; spoken /parm/ is more widely
    distributed, but the synonym arg is favored among hackers. Compare arg,
    var.


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

parm

   /parm/ Further-compressed form of param.  This term is an
   IBMism, and written use is almost unknown outside IBM shops;
   spoken /parm/ is more widely distributed, but the synonym
   arg is favoured among hackers.  Compare var.

   [Jargon File]