Interface pattern

The "interface pattern" is a very general pattern. The idea is that an "interface" is a class which provides simpler functionality to another class or group of classes.

An interface could contain a bunch of objects and provide simpler, higher-level functions to programmer (for example, the facade pattern), it could provide a cleaner or more specific way of using complicated classes (a wrapper), it could be used to act as "glue" between two different API's (the adapter pattern), and more! (Other kinds of interface patterns are: delegation, composite, and bridge).

In general, the purpose of the interface pattern is to make life easier for the programmer by simplifying things.