In process-driven organizations, process models are the basis on which their supporting processaware information systems are built. Process modeling today is a highly complex, time consuming and error-prone task. In this paper, we define the abstraction levels of process modeling and extract the business knowledge required for modeling a process. Further, we present a processoriented enterprise ontology framework for capturing all relevant aspects of process models. Finally, we provide a set of application scenarios to illustrate the usage of the ontology framework. In this way, we reduce the complexity of process modeling, enable improved enterprise transparency and help ensuring the quality of designed process models.