The circular flow refers to the continuous flow of goods, services, and money between two main sectors in an economy: households and firms. There are two types of circular flow - the real flow involving the exchange of goods and services, and the monetary flow involving the exchange of money between households and firms. In a two sector economy, households own factors of production such as labor which they supply to firms, who use these factors to produce goods and services which are then purchased by households using the income received. This continuous exchange of goods, services and money between households and firms is known as the circular flow of income.