To fully utilize web-services, users and applications should be able to discover, deploy, compose and synthesize services automatically. This automation can take place only if a formal semantic description of the web-services is available. In this paper we present the design of USDL (Universal Service Description Language), a language for formally describing the semantics of information utilized and produced by web-services. USDL is based on the Web Ontology Language (OWL) and employs WordNet as a common basis for understanding the meaning of services. USDL can be regarded as formal program documentation that will allow sophisticated conceptual modeling and searching of available web-services, automated service composition, and other forms of automated service integration. The preliminary design of USDL is presented, along with examples, and its formal semantics given.