Source : WordNet®

postfix notation
     n : a parenthesis-free notation for forming mathematical
         expressions in which each operator follows its operands
         [syn: {suffix notation}, {reverse Polish notation}]

Source : Free On-Line Dictionary of Computing

postfix notation
     
         (Or "Reverse Polish Notation", RPN) One of the
        possible orderings of {functions} and {operands}: in postfix
        notation the functions are preceded by all their operands.
        For example, what may normally be written as "1+2" becomes "1
        2 +".  Postfix notation is well suited for {stack} based
        {architectures} but modern {compilers} reduced this advantage
        considerably.
     
        The best-known language with postfix syntax is {FORTH}.  Some
        {Hewlett-Packard} calculators use it, e.g. HP-25, HP-29C,
        HP-41C, HP-23SII.
     
        Compare: {infix notation}, {prefix notation}.
     
        (2003-06-23)