Source : Free On-Line Dictionary of Computing

Stack Environment Control Dump machine
     
        (SECD machine) The first {abstract machine} for reducing
        {lambda-calculus} expressions, invented by P. J. Landin.  The
        machine has four {register}s holding pointers to {linked
        list}s operated as push-down {stack}s which hold the
        information required for the evaluation of an expression.  The
        registers point to (1) Stack which holds the arguments of
        partially evaluated expressions and results of completely
        evaluated ones, (2) Environment where the current expression
        being evaluated is stored, (3) Control which holds the machine
        instructions that manipulate the contents of the four
        registers that represent the expression being evaluated, (4)
        Dump on which the state of the machine is temporarily saved
        during the evaluation of expressions.  See also {Lispkit}.