[[Image:Droste.jpg|thumb|A visual form of recursion known as the ''[[Droste effect]]''. The woman in this image is holding an object which contains a smaller image of her holding the same object, which in turn contains a smaller image of herself holding the same object, and so forth.]]
''[['Recursion]]''' is the process of repeating items in a [[Self-similarity|self-similar]] way. For instance, when the surfaces of two mirrors are exactly parallel with each other the nested images that occur are a form of infinite recursion. The term has a variety of meanings specific to a variety of disciplines ranging from [[linguistics]] to [[logic]]. The most common application of recursion is in [[mathematics]] and [[computer science]], in which it refers to a method of defining [[function (mathematics)|functions]] in which the function being defined is applied within its own definition. Specifically this defines an infinite number of instances (function values), using a finite expression that for some instances may refer to other instances, but in such a way that no loop or infinite chain of references can occur. The term is also used more generally to describe a process of repeating objects in a self-similar way.
