Abstract: This paper proposes a new category of functions of artifacts called meta-function. Although conventional research on functional representation defines function as some kinds of abstraction of changes in objects associated with components, a meta-function of a component represents a role played by a function of the component for another function of another component without mention of such changes specific to the target system. The meta-functions explain the types of collaboration and dependency among functions of components as part of the design rationale of the target artifacts. This paper defines nine types of the meta-functions such as ToEnable and ToDrive, which form part of an ontology of functional concepts. The utility of the ontology in explanation and redesign is also discussed.