Economic theory describes in detail what difficulties arise when consumers have to handle experience goods and when they are not able to discriminate between offered goods before buying (Akerlof 1970; Nelson 1970). In order for marketplace operators to avoid such severe difficulties, they should enable users to better discriminate between offered goods and to assess relevant information about software services before buying. Software services should accordingly no longer be traded as experience goods, but rather as "search goods" whose characteristics can be assessed before buying (Nelson 1970).To describe the relevant properties of software services and hence to make their characteristics explicit, their properties ought to be described with appropriate specification approaches. Most importantly, providers should describe the business semantics a software service implements, as this is crucial for consumers when trying to identify suitable software services (Szyperski 1998). Numerous specification approaches to describe technical and quality characteristics exist. However, approaches to systematically specify the business semantics of software services are still rare. The work at hand accordingly posits the following research questions: (1) How can the business semantics of software services be systematically described? (2) Which dimensions have to be considered when describing the business semantics of software services?Aiming at answering the research questions, we propose an approach to systematically specify the business semantics of software services. The "Web Service - Business Semantics" specification approach (WS-BS) aims to fill the above discussed research gap. It can be used to explicitly describe the business semantics of software services. Describing such additional characteristics of software services shall support consumers in their assessment of suitable service candidates before purchasing a software service. Next to a classification scheme that can be used to systematically distinguish the different aspects of functionality of software services, the WS-BS specification approach provides three contributions to answer the research questions. It determines the content that should be described to specify the business semantics of software services, the way the content shall be represented, and a way to achieve a common agreement on a specification.