Dictionary.net

(SECD machine) The first abstract machine for reducinglambda-calculus expressions, invented by P. J. Landin. Themachine has four registers holding pointers to linkedlists operated as push-down stacks which hold theinformation required for the evaluation of an expression. Theregisters point to (1) Stack which holds the arguments ofpartially evaluated expressions and results of completelyevaluated ones, (2) Environment where the current expressionbeing evaluated is stored, (3) Control which holds the machineinstructions that manipulate the contents of the fourregisters that represent the expression being evaluated, (4)Dump on which the state of the machine is temporarily savedduring the evaluation of expressions. See also Lispkit.