We address the issue of ontology construction and reuse, and regard such processes as collaborative negotiations among stakeholders. A semiotic framework is proposed to model the communication environment. Accordingly, content and expression of an ontology have been clearly distinguished, and formalized independently. A twofold model is proposed: at an operational level, two stakeholders – such as designer and user – negotiate by proposing and modifying ontology fragments. At a reflexive level, the negotiation involves interpretations, until a set of shared meanings is reached; the process can be described adopting a narrative approach.