Mixins

A mixin is an interface with implemented methods. Mixins exists in .NET in the form of object oriented interfaces implementation.

Wikipedia definition of mixins

In object-oriented programming languages, a mixin is a class which contains a combination of methods from other classes. How such a combination is done depends on the language, but it is not by inheritance. If a combination contains all methods of combined classes it is equivalent to multiple inheritance.

NCop allows the notion of multiple inheritance as opposed to .NET object oriented.