E-administration requires, among others, interoperability between registers kept by authorities. Databases hold data clustered around concepts stemming from the different legal acts governing the procedures of the various authorities. Owing to the conceptual and terminological incoherence pervasive throughout legal acts, the intended interoperability between databases and registers will fail. This paper sheds light on the need for a conceptual consolidation in applicable national law on the example of registers kept by Hungarian authorities and the legislation governing them.