Classmost

Classmost is a term encountered in informal discussions of object-oriented design, used to describe the lowest common ancestor of a set of classes—in other words, the most specific common supertype that can be used to reference all members. The expression is not part of formal terminology, but it appears in design conversations as a way to discuss shared interfaces and behavior among related classes.

In design practice, identifying the classmost can guide refactoring by suggesting the extraction of a common base class or interface. This can enable polymorphism, reduce code duplication, and provide a single place to implement shared functionality. The concept is closely related to, and often overlaps with, creating a common base class or defining a shared interface that captures the behaviors used by multiple subclasses.

Example: if Circle, Square, and Triangle all implement methods like draw() and move(), a classmost might be a Shape base class or a shared interface that defines these methods, allowing code to treat instances uniformly through the common supertype.

Notes and caveats: the term classmost is informal and not standardized. Different codebases may use different naming conventions, or prefer explicit interfaces over shared base classes. Overreliance on a broad common ancestor can lead to bloated base types with low cohesion; in some cases, composition or smaller, focused interfaces may be preferable.

History: classmost does not appear in formal textbooks or language specifications and is primarily found in practitioner discussions, blogs, and code reviews. See also: lowest common ancestor, common base class, interface, polymorphism, refactoring.