PPL

from The Free On-line Dictionary of Computing (8 July 2008)

PPL

   Polymorphic Programming Language.  An interactive, extensible
   language, based on {APL}, from {Harvard University}.

   ["Some Features of PPL - A Polymorphic Programming Language",
   T.A. Standish, SIGPLAN Notices 4(8) (Aug 1969)].

   (1994-10-06)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

PPL
       Pcboard Programming Language (BBS)

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

PPL
       Polymorphic Programming Language (Harvard, Xerox, PARC)