Just like web services, business processes can be stored in public repositories to be shared and used by third parties, e.g., as building blocks for constructing new business processes. The success of such a paradigm depends partly on the availability of effective search tools to locate business processes that are relevant to the user purposes. A handful of researchers have investigated the problem of business process discovery using as input syntactical and structural information that describes business processes. In this work, we explore an additional source of information encoded in the form of annotations that semantically describe business processes. Specifically, we show how business processes can be semantically described using the so called abstract business processes. These are designated by concepts from an ontology which additionally captures their relationships. We show how this ontology can be built in an automatic fashion from a collection of (concrete) business processes, and we illustrate how it can be refined by domain experts and used in the discovery of business processes, with the purpose of reuse and increase in design productivity.