The CIMI Foundation Reference Model Module introduces important foundation classes upon which the CIMI clinical model is built. Foundation classes are not healthcare-specific and thus can serve as a foundation for other modules. The CIMI Foundation Reference Model Module introduces top-level classes for a number of hierarchies important to CIMI: the Entity, Role, Composition, and Entry hierarchies. It also introduces a number of common data structures needed to support the expressivity of this module. All classes in the Foundation Reference Model Module descend from Locatable.