Iterative, non-linear design thinking involves understanding users, challenging assumptions, redefining problems, and creating new solutions to prototype and test. As well as the set of cognitive, strategic and practical processes used by designers, design thinking encompasses the knowledge that has been developed about how people reason when solving design problems. It is also defined as 'designed ways of knowing, thinking, and acting, and 'design thinking. The study of design cognition and design methodologies has roots in the study of design thinking. Being-related branch of metaphysics describes the properties and relationships between a set of concepts and categories in a given field. In this paper, stages of Cognitive design Thinking (CDT) are defined and explained. Design thinkers solve the problem by applying the techniques in the CDT by considering all the inputs from users. Initially, the user responses are noted at the discovery phase of the design thinking. In the Ideate, Prototype stage, teams are divided, and optimal technique is applied and tested for all the inputs required by the user. Ontology web Language is used to implement the concept of CDT, resulting in generating the graphs in each phase of CDT.