APA Dictionary of Psychology

n. in generative grammar, a process in which certain grammatical rules can be repeatedly applied, with the output of each application being input to the next, in principle indefinitely. An example is the rule S→S and S, where S denotes a sentence; the rule is recursive because it can be used to generate a potentially infinite string of sentences conjoined by and. A well-known example of recursion is the nursery rhyme “The House that Jack Built” (This is the dog that worried the cat that killed the rat that ate the malt…). —recursive adj.