reference model, noun
abstract framework for understanding entities and relationships between them in a particular problem space or domain
Remark 1: A reference model is independent of the technologies, protocols and products, and other concrete implementation details.
Remark 2: A reference model is often used for the comparison of different approaches in a particular problem space or domain.
Remark 3: A reference model is usually a commonly agreed document, such as an International Standard or industry standard.