The interface between two programs consists of the set of
assumptions that each programmer needs to make about the
other program in order to demonstrate the correctness of
his own program.
A Procedure for Designing Abstract Interfaces for Device Interface Modules
An interface is a preestablished way to resolve potential
conflicts between interacting parts of a design.
An interface is an agreement about properties that an
element B should have and that other elements, such as A,
may depend upon. An interface thus comprises a set of
design rules to which B is subject and which A may assume
to be followed.
Information Hiding Interfaces for Aspect Oriented Design