recursion

Borrowed from Latin recursiō (“the act of running back or again, return”), from recurrō (“run back; return”), from re- (“back, again”) + currō (“run”).

• Rhymes: -ɜː(r)ʒən

recursion (countable and uncountable, plural recursions)

1. The act of recurring.
2. (mathematics) The act of defining an object (usually a function) in terms of that object itself.
   • 1988, Andrew Radford, Transformational grammar: a first course, Cambridge, UK: Cambridge University Press, page 128:

     However, we have still not achieved our goal of devising a finite set of rules
     which will generate an infinite set of sentence structures. In order to achieve
     this goal, we need to allow for the fact that natural languages typically have
     the property that they allow potentially infinite recursion of particular struc-
     tures. For example, one Clause can be embedded inside another indefinitely
     many times, [...]

   n! = n × (n − 1)! (for n > 0) or 1 (for n = 0) defines the factorial function using recursion.

3. (computing) The invocation of a procedure from within itself.

   This function uses recursion to compute factorials.

• tail recursion
• infinite recursion

• recur
• recurrent
• recurrence
• recurse
• recursive
• recursivity

• coinsurer