When we speak of legal language , we refer to a mode of communication that works hard to convey a degree of precision that clearly establishes the extent and limits of rights and obligations between parties. This endeavour must strive to overcome numerous obstacles - notably societal context and ideology - that are ineluctably present in language itself. And when legal bonds apply internationally, problems of translation add yet another and more complex dimension. It can be said that these problems of language and meaning particularly affect the application of labour law and social security law, as these legal regimes colour the day-to-day lives and livelihoods of virtually everybody. This volume assumes the monumental task of codifying the terminology of European labour law and social security law in English, French, German, Spanish and Italian. The initial classification follows the 15 European legislative acts that cover the field. For each of these acts, all the terms and notions are listed (in alphabetical English order) with their definitions as provided in the legislation itself and the interpretations given to them in the case law of the European Court of Justice - all in five languages. In this way, the full spectrum of potential misunderstanding and contradiction is exposed, and all relevant subtleties come into clear focus. This efficient aggregate of vital material gives both practitioner and academic the means to make as complete a judgement as possible concerning the application of European labour law and social security law in any context.