Comprehensibility of the ontological model as a characteristic of its quality

There is a tendency to combine professional knowledge within the framework of the creation of cyber-physical systems. This encourages making them available to a wide range of stakeholders. Various models of knowledge representation are considered from the standpoint of historicism and levels of community. It is proposed to add an interdisciplinary (general scientific) level to the three levels of knowledge representation according to the degree of its generality - philosophical, narrowly disciplinary (professional) and subject level (knowledge base). It is argued that any model of knowledge representation is based on the model of a formal system and its child model, the predicate calculus. A labeled graph is a visual model for representing knowledge. A generalized model that reflects the relationship between knowledge and cognition is proposed. Understanding the model of knowledge is interpreted as a means of cognition. The term of comprehensibility of the ontological model is introduced as a property that most characterizes its quality. The comprehensibility of the ontological model is divided into verbal and systemic ones. The factors influencing these components of model comprehensibility are discussed. Indicators for measureing the clarity of the ontological model are proposed.