Organizations have experienced for the past 40 years mass computerization, the advent of the Internet and dematerialisation of documents, moving from document management towards managing the overflow of information and nowadays data. Meanwhile, their functioning evolves from top-down to transversal approaches, and their contexts require an operational mobilization of information and knowledge. The response of the organizations is generally sought in ICT tools, whose accumulation makes the problem more complex. We present here a specific case illustrating the need to enhance the organisations’ knowledge heritage. We explain why upstream contextualization work is essential, in order to situate the operating mode of the SI in a larger structural problem. In this context, the core business of the company appears as the basis of any reflection. Their terminology is the key we use to improve better management of the documentary heritage and knowledge they transmit, through a knowledge database based on a domain ontology.