In common, national income means the total value of goods and services produced annually in a country. In other words, the total amount of income accruing to a country from economic activities, in a year's time is known as national income. It includes payments made to all resources in the form of rent, wages, interest and profits.
Thus, national income is the aggregate monetary -value of all final goods and services produced-in the, economy in a year.
Definitions of National Income:
Dr. Marshall's Definition
Marshall's definition represents a total value of production - it is from production end.
According to Marshall, "The labour and capital of a country acting on its natural resources produce annually a certain net aggregate of commodities, material and immaterial including services of all kinds.... This is the true net annual income or revenue of the country or national dividend."