5.1. Institutional units were defined in chapter IV. The present chapter, which starts off with a view of institutional units in their capacity as producers, defines an institutional unit engaged in production as an enterprise. An enterprise may be a corporation (a quasi-corporate enterprise being treated as if it were a corporation in the System), a non-profit institution, or an unincorporated enterprise. Corporate enterprises and nonprofit institutions are complete institutional units. An unincorporated enterprise, however, refers to an institutional unit—a household or government unit—only in its capacity as a producer of goods and services. It covers only those activities of the unit which are directed towards the production of goods or services. Many households do not contain an unincorporated enterprise.