Although there have been great advances in business process modeling as a means to better understand and control organizations and improve the development of information systems, the existence of functions - like IT, logistics, financial, etc. - is an inescapable reality in organizations, that strongly influences aspects like change processes, or the formation of organizational units, even if a culture of "process orientation" is established. This paper tries to clarify the concept of organizational function, discusses certain organizational artifacts that seem to be of a functional nature and proposes an ontology for the purpose of allowing a consistent and coherent modeling of this recursive self-maintenance mechanism of organizations.