||System interoperability proposals have been, until now, largely based on textcontents. IFC, STEP, XML are languages or standards that need a consensualsignification behind their terms. Each term can have many different meanings,depending on the context in which it is inserted and to include a full description ofeach one in every document is too complicated and irksome. It would be necessary,somewhat, to be able to select the meaning respecting the context, and this wouldprobably consume too many resources.Any text-based system must run over a terminology which is well accepted andperfectly understood by its users. This is one of the main obstacles encountered inreaching full interoperability. Not only because we seldom have, in any language, atechnical dictionary for the construction field, which could work as an officialreference, but also due to the difficulties of translating between languages. Distinctbuilding cultures and organisations make it difficult to obtain a proper translation.One way to overpass this hindrance is to develop a reference constructionterminology, including concepts description and terms interrelationship. Theconcepts must be associated with a conceptual map, which reflects termsassociations and pertinence. This map can be linked to the OCCS OverallConstruction Classification System, in order to make the correlation easier.The relationships established through this conceptual map can be easily translatedto any system, especially to XML schemes and data descriptions, making it possibleto fulfil a real interoperability.Building this terminology is the aim of a Brazilian government- sponsored project,so called CDCON, now in course under the co-ordination of a group of universitiesand participation of building contractors, suppliers associations and systemsdevelopers.