The E uro V oc Thesaurus: Management, Applications, and Future Directions (2025)

Abstract: This paper provides a comprehensive overview of EuroVoc, the European Union’s multilingual thesaurus. The paper highlights EuroVoc’s significance in the legislative and publications domain, examining its applications in improving information retrieval systems and multi-label text classification methods. Various technological tools developed specifically for EuroVoc classification, including JEX, PyEuroVoc, and KEVLAR, are reviewed, demonstrating the evolution from basic classification systems to sophisticated neural architectures. Additionally, the paper addresses the management practices managing EuroVoc’s continuous updating and expansion through collaborative tools such as VocBench, emphasising the role of interinstitutional committees and specialised teams in maintaining the thesaurus’s accuracy and relevance.A substantial part of the paper is dedicated to EuroVoc’s alignment with other semantic resources like Wikidata and UNESCO, detailing the challenges and methodologies adopted to facilitate semantic interoperability across diverse information systems. Finally, the paper identifies future directions that include modular extensions of EuroVoc, federated models, linked data approaches, thematic hubs, selective integration, and collaborative governance frameworks.

## introduction the european union's legislative framework encompasses a vast array of documents across multiple languages, necessitating robust systems for organisation and retrieval. eurovoc 1 stands as a cornerstone in this infrastructure as a comprehensive multilingual thesaurus specifically designed to systematise eu legislative documentation. despite its instrumental role in numerous research experiments and practical applications, as evidenced by multiple published studies (see section 1.1), a comprehensive examination of eurovoc as a foundational resource has remained notably absent from the literature. this paper addresses this significant gap by providing an in-depth analysis of eurovoc's structural features and functional capabilities. furthermore, we examine the ongoing efforts within european institutions to align eurovoc with other semantic resources, enhancing its interoperability and utility. ## management of eurovoc the effective management of eurovoc is essential to maintaining its role as a comprehensive, multilingual thesaurus that supports the indexing and retrieval of eu-related documents. originally created to process documentary information, eurovoc has evolved to cover a wide range of domains. its management involves a structured approach to ensure that the thesaurus remains up-to-date, relevant, and accessible to users across the eu and beyond. eurovoc's structure and content supports precise classification and retrieval across thematic areas such as politics, law, and economics and its multilingual availability in all 24 official eu languages promotes cross-border information exchange. the governance of the thesaurus involves multiple layers of collaboration and oversight, including an interinstitutional committee and a dedicated reference data team. this team coordinates contributions, edits the thesaurus, and oversees its publication, ensuring adherence to international standards for terminology and thesaurus management. furthermore, eurovoc's integration of semantic web technologies and alignment with the simple knowledge organization system (skos) model underscores its adaptability and integration into modern digital information systems. eurovoc publishes semi-annually across platforms like the cellar semantic repository and the eu vocabularies website, ensuring both machineand human-readable access. by leveraging collaborative tools like vocbench @xcite foot_0 and engaging a diverse working group of professionals, eurovoc remains a dynamic resource that continually adapts to new challenges and requirements. this section explores its management, content, structure, and publication processes, highlighting the collaborative and technological frameworks that support its ongoing development. ## use of eurovoc eurovoc is used to categorise and index documents, from legislation to general publications and library resources, facilitating the organisation, the search and retrieval of information related to eu activities. it is used in various document management systems, databases and websites of eu institutions, in eu institutional and national government libraries as well as in academia and research institutes. in the following chapter we highlight a few use cases of eurovoc in the publications office and in eu institutions. ## alignments between eurovoc and other multilingual vocabularies alignments establish correspondences between concepts, creating a comprehensive, interconnected knowledge ecosystem that improves information retrieval and multilingual access. for example, in figure 11 a simple query over the wikidata sparqlendpoint returns the alignments between eurovoc and the unesco thesaurus. however, they imply significant challenges: they constantly evolve, requiring considerable maintenance, often lacking dedicated tools to assist in the process, as well as necessitating restarting alignment procedures from scratch when updates occur. in the following paragraphs we show how these challenges are addressed at the publication office of the european institutions. ## conclusions and future directions this paper has provided an extensive review and analysis of eurovoc, the multilingual thesaurus employed by the european union for annotating eu documents. it has detailed eurovoc's structural characteristics, management practices, and its importance in enhancing legislative document retrieval and multi-label text classification. the paper examined various technological tools such as jex, pyeurovoc, and kevlar that demonstrate eurovoc's evolution and increasing sophistication. moreover, it addressed significant challenges and strategies involved in maintaining semantic interoperability with other resources like wikidata and unesco. through this comprehensive analysis, the paper underscored eurovoc's role as a critical semantic resource within eu institutions. future work future directions should explore several innovative and practical approaches to enhance eurovoc's effectiveness, adaptability, and sustainability. drawing from scenarios analysed in relation to eu agencies' specific needs, modular extensions and federated models could offer valuable frameworks that allow for flexibility, scalability, and semantic consistency. linked data strategies and thematic hubs could further optimise semantic interoperability without overwhelming the core thesaurus structure. selective integration methods would help maintain targeted growth, ensuring eurovoc remains concise and relevant. to advance these strategic directions, collaborative governance frameworks should be considered to distribute maintenance responsibilities effectively among eu agencies. dynamic concept expansion, leveraging advanced ai-driven semantic elicitation tools, could automate and refine the identification and integration of relevant emerging concepts. controlled vocabulary sets provided by agencies might also offer a structured yet flexible means of expanding eu-rovoc's coverage without compromising manageability. additionally, further integrating advanced artificial intelligence methods could significantly boost eurovoc's utility and operational efficiency. employing natural language processing and large language models could greatly enhance multilingual semantic tagging, classification accuracy, and automated ontology alignment. ai-driven analytics could proactively identify emerging concepts and semantic shifts, ensuring eurovoc remains current and responsive to evolving legislative language and domains. moreover, using ai-powered recommender systems could personalise user interactions, streamline content discovery, and improve overall user satisfaction. beyond these documented scenarios, additional recommendations include adopting advanced machine learning techniques for automated multilingual translations, quality control, and conflict resolution, thus addressing the semantic warrant challenges identified by @xcite . enhancing user interfaces with intuitive search functionalities and adaptive visualisations would improve end-user experiences, facilitating easier navigation of an expanded thesaurus. implementing robust version control and dependency tracking within vocbench would enhance management capabilities. finally, regular stakeholder training programs and feedback mechanisms could ensure that eu-rovoc continues to evolve in alignment with the evolving informational landscape and user requirements across the eu institutions, extending the foundation established by @xcite .