A type or classification to which all similar objects belong.

The highest-level element in an object-oriented programs; classes contain both functions (methods) and data. Collaboration: A class 's interaction with other classes to carry out all its necessary responsibilities; needed when the class by itself does not know or can not do everything it needs to know or do.The final step in object-oriented analysis is to identify the class's collaborators.

The definition of a complex type in object oriented programming. Classes contain attributes to store information specific to their instances and methods to provide the operations that define their behaviour.