Public policies documents convey strategic directions and framework of actions of government in a particular sector. For most societal challenges, there is a need for government entities at the same and different levels to coordinate their policies and collaborate on the implementations of policies. However, this coordination and collaboration efforts are seriously hampered by the lack of a central repository for public policy documents from which policy makers and researchers can access related policies on a particular topic, industry or group of stakeholders. To address this challenge, this paper describes the development of Vocabulary to underpin the implementation of a shared public policy repository in Europe. The Core Public Policy Vocabulary (CPPV) is developed as a semantic interoperability resource for government organizations for consistent description and documentation of public policies to enable efficient discovery, cross-referencing and analysis of policy documents. We describe our approach, conceptual model, elements of the vocabulary, its implementation and concrete scenarios for the use of the vocabulary.