Abstract
A taxonomy of generic functions plays a crucial role in managing the functional knowledge. In functional taxonomy, even though each functional term is captured by various viewpoints or classifications, its classification criteria are implicit. For revealing the functional classification criteria, this article discusses the organization of them. Firstly, we specify classification criteria in functional taxonomy. Secondly we organize functional classification criteria based on the relationship between them. It can contribute to specify not only the definition of each functional term in functional taxonomy but also what type of functional classification criteria exists in general when we classify the functional concepts.
