What term describes the relationship between two or more classes?

The term that describes the relationship between two or more classes is "Association." This term refers to a general connection between classes where one class can reference or use another class. It indicates a relationship where instances of one class can relate to instances of another class, facilitating various kinds of interactions and dependencies between them.

Association is often depicted in UML (Unified Modeling Language) as a solid line connecting two class boxes, with optional arrows indicating the direction of the relationship. This relationship can also be bi-directional, meaning that both classes can reference each other. For example, in a library system, a Book class might be associated with an Author class, showing how books can have authors and authors can write multiple books.

Other terms such as Composition, Aggregation, and Inheritance describe more specific types of relationships and imply different degrees of ownership or life-cycle dependencies between classes. For instance, Composition implies a strong ownership where one class is a part of another, while Aggregation represents a weaker relationship. Inheritance relates to a hierarchical relationship where one class derives from another, allowing it to inherit properties and behavior. However, Association encompasses a broader range of interactions without implying strong ownership or hierarchy, making it the correct choice in this context.