Source : Free On-Line Dictionary of Computing

string reduction
     
        A {reduction system} where an expression is represented as a
        string of function names, constants and parentheses.  It is
        reduced by replacing parts of the string representing subterms
        by their value.
     
        It is harder to represent sharing of subexpressions in string
        reduction than in {graph reduction}.
     
        (1995-02-06)