In my latest contacts with clients, they keep coming up with an ontology. The question then arises: is this a new hype or a solid and essential concept for the future? The client's question proves the increasing interest in ontologies in recent years, due to the need for semantic clarity and data integration. It is not a new concept but has been a fundamental part of science for decades. The concept of ontologies emerged from a philosophy concerned with the nature of existence and the categorization of things. In the 1990s, ontologies were an important part of information, artificial intelligence, and semantics. It is not a new phenomenon, but the link with AI makes clear the revival of a proven and sustainable approach. With an increasingly complex and diverse data landscape, an Ontology provides a structured way to capture the tokens of data and define relationships between entities. Problems such as data silos, interoperability or semantic inconsistency are not temporary. If we coll