In programming languages and type theory, polymorphism is the provision of a single interface to entities of different types or the use of a single symbol to represent multiple different types.
The most commonly recognized major classes of polymorphism are:
- Ad hoc polymorphism: defines a common interface for an arbitrary set of individually specified types.
- Parametric polymorphism: when one or more types are not specified by name but by abstract symbols that can represent any type.
- Subtyping (also called subtype polymorphism or inclusion polymorphism): when a name denotes instances of many different classes related by some common superclass.
