(1) A set of classes that embodies an abstract design for solutions to a family of related problems.
(2) A set of class libraries encompassing the following: Functions (or set of functions) of a particular domain arranged in an inheritance hierarchy. An encoded model for use of the framework that defines the relationships between the classes in the framework and the rules that govern their use. Frameworks call the code; the user does not call the frameworks.
(3) A set of object classes that provide a collection of related functions for a user or piece of software.
(4) A micro-architecture that provides an extensible template for applications within a specific domain.