Clarity in semantics and a rich formalization of this semantics are important requirements for ontologies designed to be deployed in large-scale, open, distributed systems such as the envisioned Semantic Web. This is especially important for the description of Web Services, which should enable complex tasks involving multiple agents. As one of the first initiatives of the Semantic Web community for describing Web Services, OWL-S attracts a lot of interest even though it is still under development. We identify problematic aspects of OWL-S and suggest enhancements through alignment to a foundational ontology. Another contribution of our work is the Core Ontology of Services that tries to fill the epistemological gap between the foundational ontology and OWL-S. It can be reused to align other Web Service description languages as well. Finally, we demonstrate the applicability of our work by aligning OWL-S' standard example called CongoBuy.
