What is "duck typing"

n. (context computing programming English) A style of dynamic typing in which an object's current set of methods and property determines the valid semantics, rather than its inheritance from a particular class or implementation of a specific interface.

In computer programming, duck typing is an application of the duck test in type safety. It requires that type checking is deferred to runtime, and is implemented by means of dynamic typing or reflection.

Duck typing is concerned with establishing the suitability of an object for some purpose. With normal typing, suitability is assumed to be determined by an object's type only. In duck typing, an object's suitability is determined by the presence of certain methods and properties (with appropriate meaning), rather than the actual type of the object. The analogy to the duck test appeared in a Python Enhancement Proposal discussion in 2002.