A conceptual model of a computer (or a computer program) which represents the computation in terms of a finite number of states and transitions between them. This is the closest commonly used paradigm to both the TuringMachine and JohnVonNeumann's automata, and is widely used in parsers. Often implemented with the much-maligned GoTo.

One of the fundamental proofs in ComputerScience is that any result calculatable on a FiniteStateMachine is calculatable in LambdaCalculus.