Conceptual modeling is about describing the semantics of systems at a high level of abstraction. Specifically, conceptual modelers (1) describe structure models in terms of entities, relationships, and constraints; (2) describe behavior or functional models in terms of states, transitions among states, and actions performed in states and transitions; and (3) describe interactions and user interfaces in terms of messages sent and received and information exchanged. In their typical usage, conceptual-model diagrams are high-level abstractions that enable clients and analysts to understand one another, enable analysts to communicate successfully with application programmers, and in some cases automatically generate (parts of) the software application.

Keywords: Entity-Relationship Model, ER Diagram, Conceptual Schema Design, Model-Driven Software Development, Model-Driven Architecture (MDA), Model Centered Architecture (MCA), Domain Specific Modeling Language (DSML), Unified Modeling Language (UML), Enterprise Modeling, Extended ER Model, Enhanced ER Model, Object Role Modeling, Process Modeling, Business Process Modeling, Workflow Design, Foundational Theory of Conceptual Models and Conceptual Modeling.