This paper proposes the design of an ontology of multiple programming languages and give three examples to show the methodology. Our ontology aims to summarize the core of computational thinking logic by elaborating the concepts of three object-oriented programming languages in the industry: Python, Java, and C#. Therefore, the construction of the ontology lies not only on these three programming languages but also on their common concepts. This kind of ontology design facilitates the ontology extension and merging when concepts of other programming languages are added in the future. This ontology could be used to not only provide a guideline for any research work focusing on computational thinking education but also describe the common concept of visual programming tools and existing programming languages. Based on this ontology, an adaptive tutoring system intended to provide learners with personalized programming exercises, is under development.