PPN

PPN /P-P-N/, /pip'n/ n.  [from `Project-Programmer
   Number'] A user-ID under {{TOPS-10}} and its various mutant
   progeny at SAIL, BBN, CompuServe, and elsewhere.  Old-time hackers
   from the PDP-10 era sometimes use this to refer to user IDs on
   other systems as well.