Terminological confusion about social entrepreneurship derives largely from the fact that social enterprises are structurally hybrids in several dimensions. Hybridity is their essential characteristic and it fulfills an indispensable role. An approach is developed that does not rest on dichotomous distinctions by sectors or profit orientation. On the basis of a reconstruction of the essential components of entrepreneurship, a generic structure of social entrepreneurship is proposed which in turn is founded upon enterprise ontology. It emphasizes the entrepreneurial nature of such ventures in the sense of real causation.