This document provides a Glossary focused on providing practical help to the following users: Those drafting or interpreting legislation. Those seeking to interpret terms which might be used or defined in one context to apply them in another context. Those needing to develop an understanding of commonly used terms which might have a specialist meaning in contexts of which they are unaware. Those developing ontologies intended to cover domains which are not yet fully covered by their own set of unambiguous definitions. This project s methodology consisted in a first phase to investigate EU legislations which might have an impact on the management of data used in Europe in the various transport domains. At the end of March 2025, more than 250 legislations had been identified which could contains relevant terms and definitions. Taking into consideration the timeframe of the OpRa+ project it was decided to develop the comparison work from this list, from which 43 legislations (as amended as of March 2025) have been selected to record in an Excel file the official definitions they contained. As a whole, the definition of a total of 717 terms has been provided in an Excel file which also detailed the scope of the selected legislations. This Excel file has been in a second phase consolidated with the Transmodel-v6.2-Data-Dictionary into a new file named OpRa exhaustive glossary issued on 7 May 2025 which contains 2336 definitions of terms. Then the methodology focused on the redundancy of the terms in the legislations which highlighted from the various sources 72 terms redundant between 2 and 6 times. Even though only a limited number of terms are covered explicitly in this document, hopefully the recommendations provided for the listed terms can inspire the intended Audience to use an analogous approach when defining or selecting terms to be used when drafting legislation or developing ontologies. This Glossary was last updated using the legislation available in March 2025. Readers need to be aware that some regulations, standards and other referenced material are undergoing active development and therefore the latest versions available at a later date might contain differences to these reviewed. The Glossary contains a separate section for each of the 30 selected terms. Each such section contains sub-sections detailing the contexts the term is used in, related terms, any unifying concept, source references to the full definitions, and usage recommendations. The following section describes this in more detail.