The Modernising Energy Data Access (MEDA) competition was set up by Innovate UK and the Modernising Energy Data group to help develop the concept of a Common Data Architecture (CDA) for the Energy Sector. One of the main goals of the Common Data Architecture is to improve data sharing across the energy sector and make data more interoperable across organisations. In order to effectively understand and combine data from disparate sources, it is necessary for the data provider and data user to have a common understanding of the key concepts and terms used in the data. However, the lack of authoritative definitions or standards in the energy sector means that this is often not the case. In addition, the National Digital Twin Programme has identified that it will be important to extend this common understanding across the wider economy to ensure that data is interoperable and understandable across traditional sector boundaries. Within this page we will document existing Glossaries and Vocabularies from across the energy sector, analyse these to identify overlaps, disagreements and gap and begin to reconcile issues for a number of key use cases that have been identified in the MEDA competition.