Coupling of interorganizational business processes in electronic markets is a difficult and time-consuming task. In practice, business processes are geographically distributed, which makes it particularly difficult for business partners to coordinate their supply chains and customer relationship management with business units. By using formal description languages such as Petri Nets for modeling interorganizational business processes, purely syntactic composition problems of distributed business environments can be solved. However, the missing semantic representation of Petri Nets can hamper the interconnectivity of business processes. Usually, several business partners, even if they share similar demands, have their own specific vocabularies. By representing business processes with Petri Nets in combination with the Web ontology language (OWL), our approach provides flexibility, ease of integration, and a significant level of automation of loosely coupled business processes even if they do not share their respective vocabularies.