psi

from WordNet (r) 3.0 (2006)

psi
    n 1: a unit of pressure [syn: {pounds per square inch}, {psi}]
    2: the 23rd letter of the Greek alphabet

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

Portable Scheme Interpreter
PSI

   (PSI) A portable scheme interpreter by Ozan Yigit
   <[email protected]>, David Keldsen and Pontus Hedman that
   includes a simple {DAG} compiler and a {virtual machine}.  It
   can be used as an integrated extension {interpreter} in other
   systems and allows easy addition of new primitives.  There are
   some unique debugging and tracing facilities.  Acceptable
   performance results from a fairly straight-forward
   implementation.  {Continuations} are fully and portably
   supported and perform well.  PSI is based on the simple
   compilers and {virtual machine} in Kent Dbyvig's thesis.

   The pre-release version conforms to {R4RS} with a number of
   useful extensions.

   (1993-02-19)

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

PSI
       Performance Systems International, inc.

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

PSI
       Published Subject Indicator (XTM)