Terminologies play a critical role in semantically linking research data management (RDM) across disciplines. They provide the basis for consensus definitions of entities, thereby ensuring conceptual alignment, even when the nomenclature differs between domains. The use of standardised terminologies promotes interoperability and data integration, as data described through common terminologies can be understood and used across different sources and disciplines significantly improving their reusability. Currently, NFDI consortia are working with terminologies at different stages of maturity and FAIRness. Terminologies are used in various services and tools to annotate and link research. To support these tasks, several terminology services (TSs) have been developed to publish, provide, describe, and curate terminologies.Their alignment, management, curation, and further development are challenging but necessary tasks. They involve consensus building and harmonisation across disciplines. The envisaged Terminology Services 4 NFDI (TS4NFDI) aims to standardise and harmonise terminology management within the NFDI, thereby facilitating consensus-building and interoperability of services across disciplines to achieve a shared knowledge representation and knowledge engineering framework. The service seeks to integrate and converge individual solutions into a standardised, interoperable, and sustainable service suite with Service Wrapper, API Gateway, mapping service, and re-usable GUI widgets.