Feature modeling, a conceptual domain modeling technique used mainly in domain engineering, proved as useful for representing configurability of concepts by dealing explicitly with commonality and variability. This paper introduces feature modeling for multi-paradigm design as an integrative approach and evaluates other approaches to feature modeling. These approaches differ mainly in the notation of feature diagrams, but there are also differences regarding the basic notions. The commonalities and variabilities of the domain of feature modeling are concisely expressed using feature modeling itself in the form of a feature modeling metamodel which may serve both for further reasoning on feature modeling and as a basis for developing feature modeling tools.